Nordic Road and Transport Research 3-2004

N R & T R No 3 • 2004

News from Denmark, Finland, Iceland, Norway and Sweden

Traffic Information Centre – page 22

Editorial notes Nordic Road & Transport Research is a joint publication of six public road and transport research organisations in the Nordic countries, Denmark, Finland, Iceland, Norway, and Sweden. The main objective of the publication is to disseminate research results and news from the institutions, especially to researchers and decision makers. Each institution is responsible for the selection and presentation of the material from its own scope of activities.

Nordic Road & Transport Research is published three times a year. It is regularly sent out, free of charge, to recipients selected by the six joint publishers. Free sample copies are also sent out on special request.

Reproduction and quotation of the texts are allowed if reference is made to the author and source. However, legislation regulates and restricts the right to reproduce the illustrations.

Please contact the respective publishing institution for information.

Advertising is not accepted.

Correspondence about the contents of the publication: Please write to the author or to the respective publishing organisation.

Requests for back issues, and notification of address changes: Readers outside the Nordic countries: please write to the Editor-inchief at the VTI in Sweden.

Readers in the Nordic countries: please contact the publishing institution of your country.

Addresses: see back cover.

The Editorial Board consists of the following representatives of the publishing institutions Editor-in-Chief Tarja Magnusson, Swedish National Road and Transport Research Institute Denmark Helen Hasz-Singh, Danish Road Institute Finland Kari Mäkelä, Technical Research Centre of Finland, Building and Transport Iceland Hreinn Haraldsson, Public Roads Administration Norway Thorbjørn Chr. Risan, Norwegian Public Roads Administration Harald Aas, Institute of Transport Economics Production: Johnny Dahlgren Grafisk Produktion AB Place of publication: Linköping, Sweden Issue: 3,500 ISSN 1101-5179 Cover photo: Traffic Information Centre at the Danish Road Directorate.

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N R & T R Volume 16 • No. 3 • December 2004

Danish Road Directorate (DRD) Danish Road Institute (DRI) The Road Directorate, which is a part of The Ministry of Transport, Denmark, is responsible for development and management of the national highways and for servicing and facilitating traffic on the network. As part of this responsibility, the Directorate conducts R&D, the aim of which is to contribute to efficient road management and to the safe use of the network. The materials research component is carried out by the Danish Road Institute.

Technical Research Centre of Finland (VTT), Building and Transport VTT Building and Transport, employing a staff of 450, is one of the eight research units of the Technical Research Centre of Finland (VTT), with a total staff of 3,000. VTT Building and Transport covers all fields of transport and road engineering.

The unit is active in international research and has a prominent role on the national level.

Public Roads Administration (PRA), Iceland The duty of PRA is to provide society with a road system according to its needs and to offer service aiming at safe, unobstructed traffic. The number of employees is about 340.

Applied research concerning road construction, maintenance and traffic and safety is to some extent performed or directed by the PRA. The authority with its Research and Development division is responsible for road research in Iceland.

Norwegian Public Roads Administration (NPRA) The Norwegian Public Roads Administration is one of the administrative agencies under the Ministry of Transport and Communications in Norway. The NPRA is responsible for the development and management of public roads and road traffic, as well as the Vehicle Department. This responsibility includes research and development of all areas related to road transport, and the application of R&D products.

Institute of Transport Economics (TØI), Norway The Institute of Transport Economics is the national institution for transport research and development in Norway. The main objectives of the Institute are to carry out applied research and promote the application and use of results through consultative assistance to public authorities, the transport industry and others. The Institute is an independent research foundation employing about one hundred persons.

The Swedish National Road and Transport Research Institute (VTI) carries out research and development work of an internationally high standard for the transport sector. Our work embraces all modes of transport. Our key expertise is in the fields of safety, economy, environment, traffic and transport analysis, behaviour and the human-vehicle-transport system interaction, as well as in road design and infrastructure maintenance. VTI is a world leader in several areas. The Institute is state-owned and has a total of 180 employees.

NORDIC ROAD & TRANSPORT RESEARCH NO. 3 2004

CONTENTS Technical Research Centre of Finland (VTT), Building and Transport

Potential Harmonisation of Variable Message Signs in Viking Countries . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4

Institute of Transport Economics (TØI)

Aggressive Drivers Increase the Accicent Risk . . . . . . . . . . . .6 Road Investments in Oslo Did Not Induce New Traffic . . . . .8 Increased Penalties Make People Use the Seat Belt . . . . . . .9

Swedish Road and Transport Research Institute (VTI)

With Tiny, Tiny Particles in View . . . . . . . . . . . . . . . . . . . . . .10 VTI-algorithm Structuring the Austrian Road Network . . .12 Designing and Testing a School Transportation Bus Stop . .14 Driving when Tired – from the Drivers’ Point of View . . . .15

Norwegian Public Roads Administration (NPRA)

Sand, Salt and Hot Water in Winter Road Maintenance . .16 Toll Financing – How to Reduce the Operating Costs? . . . .19

Danish Road Directorate (DRD)

The Traffic Information Centre Seen in an International Perspective . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .22 Recycling in Roads Has Been Upgraded . . . . . . . . . . . . . . . . . . . . .24 Noise from Road Humps . . . . . . . . . . . . . . . . . . . . . . . . . . . .26

Annotated reports . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .28

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TECHNICAL RESEARCH CENTRE OF FINLAND (VTT), BUILDING AND TRANSPORT

Potential Harmonisation of Variable Article written by Pirkko Rämä, Anna Schirokoff and Juha Luoma.

The study was designed to gain information about variable message signs (VMS) and their appearance and use in the Viking countries, and to utilise this information for enhancing the harmonised use of VMS. The Viking countries include Denmark, Finland, Norway, Sweden and the five northernmost states in Germany.

Harmonisation is being motivated by safety and efficiency demands in the EU countries. The technologies used in advanced traffic systems are currently being developed and therefore there is an increasing use of VMS. Hence there is a growing need for uniform systems.

Harmonisation in Europe

There have been several efforts to improve the harmonised use of VMS at the European level. The aims of this harmonisation are to increase the conformity and efficiency of the messages provided

by VMS, and to improve traffic safety and mobility. Harmonisation also benefits manufacturers by providing common specifications for all parties involved.

Efforts for the more harmonised use of traffic signs should be based on international commitments, with the Vienna Convention (1968) being the most binding. The UNECE (United Nations Economic Commission for Europe), with its annual meetings and working parties (especially WP 1), is the international body for the further development of international commitments in the area of sign harmonisation. In addition, there are international and European recommendations (previously made e.g. by CEMT) and standards. European road directors (WERD/DERD) have examined the harmonised use of VMS, and published the paper “Action FIVE: Framework for 4

Harmonised Implementation of VMS in Europe”. This work has been continued by the European VMS Platform. In addition, several research studies have dealt with the harmonised use of VMS, both within EU R&D Framework Programmes and within national projects.

Appearance and use

This study was designed to gain information about VMS and their appearance and use in the Viking countries, and to utilise this information to enhance the harmonised use of VMS in the Viking region.

Harmonisation needs were specified and prioritised.

Although this Euro-regional Viking project focused on the Northern countries, it was assumed that focusing on regional circumstances and problems would promote both regional and Europe-wide harmonisation work.

Furthermore, this progress could facilitate the creation of a specific programme for harmonisation work in the future. It is emphasised, however, that it is vital to be aware of European commitments and harmonisation work, and to make suggestions in line with other activities and know-how at the European or international level.

This study focused on harmonisation issues from the drivers’ point of view, i.e. how the drivers perceive and comprehend VMS. The technical harmonisation (durability, luminance specifications etc.) is another extensive field and will be covered by the new standard prEN 129 66-1. It is expected that the technical specifications in the standard will coordinate the appearance of VMS as well.

Sign experts and research results

The data was collected by a questionnaire, a workshop and literature studies covering previous activities and research into the area. Firstly, the questionnaire was sent to traffic sign experts in each country in the autumn of 2003. The ques-

All the Viking countries preferred speed limit signs that use inverted colours and LED (Light Emitting Diode) or fibre-optic technology.

tionnaire concerned the current practice and deployment of VMS in a given country. The questions concerned the three main sign categories (regulatory messages, danger warning signs and informative signs) as well as several sub-issues and some general aspects. Secondly, a workshop was held during which the results of the survey were completed. Thirdly, the report summarised the relevant results of both research and more practical actions in the field of VMS harmonisation in Europe.

Harmonisation needs in four categories

Conclusions summing up the harmonisation needs were presented priority-wise for each sub-issue (Table 1). In addition, the results identified several VMS featu-

NORDIC ROAD & TRANSPORT RESEARCH NO. 3 2004

TECHNICAL RESEARCH CENTRE OF FINLAND (VTT), BUILDING AND TRANSPORT

Message Signs in Viking Countries res and practices that have already been harmonised and differences, which do not initiate any harmonisation measures.

There are differences in the usage areas and the needs to use variable systems, depending on the country. The most harmonised areas are the colours and the use of symbols and pictograms in regulatory and danger warning signs. There are more variations and they are acceptable in informative messages. But also in this sign category, pictograms are preferred to text messages, and excess information is to be avoided.

Harmonisation work

Common targets for both the short-term and long-term harmonisation are the development of systems reliability, the amount of information presented, the use and development of pictograms and the use of flashing lights in VMS. Several more specific issues, which were to be considered for harmonisation in the short term, were identified in the study. For example: • light-emitting signs with inverted colours are preferable when planning new variable speed limit systems and developing old ones • the use of flashing lamps in speed limit signs has to be well-motivated and should be studied carefully, especially when developing new systems • weather- and traffic-based control should be included in variable speed limits at sites, where both weather and traffic problems occur • the accident pictogram (suggested by FIVE) should be confirmed at the national level if an overall consensus can be reached (e.g. at the UNECE-level) • the current definitions for the maximum length of text messages should be unified • international expressions should be preferred in text messages and it is suggested that a data bank of the messages used in the Viking language area should be created

Table 1. The structure of the document and a summary of the conclusions. The colours indicate the degree of harmonisation in the Viking countries.

• more information on VMS qualities should be provided to road users.

The long-term harmonisation needs to be identified in the study included: an increased level of automation in the weather-controlled systems, more uniform control principles for warning signs, a tested and commonly accepted re-routing arrow, and more harmonised message absence practices for lane signals and the more uniform use of amber lanterns in lane control.

Currently, the issues concerning variable signs are being discussed in several international groups. The harmonisation process should be continued by the national road authorities of the Viking coun-

NORDIC ROAD & TRANSPORT RESEARCH NO. 3 2004

tries in joint co-operation. Finally, as the use of VMS systems will probably increase, it is recommended that this report should be updated in a couple of years' time.

Title: Practice and deployment of variable message signs (VMS) in Viking countries – Potential for harmonisation Authors: Pirkko Rämä, Anna Schirokoff and Juha Luoma Series: Finnra reports 34/2004 Language: English

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Studies indicate that the prevalence of aggressive driving is likely to increase during certain traffic situations, for instance unexpected obstructions like queue outside rush-hour.

Aggressive Drivers Increase the Accident Risk Author: Pål Ulleberg.

Several studies indicate that aggressive or reckless driving may increase the risk of traffic accidents. The most dominant ones are excessive speeding, tailgating, failure to yield the right of way for other road users and red-light running. At the same time, explicit aggressive acts like rude gesturing, flashing headlights, sustained horn-honking and yelling do not seem to increase the accident risk, according to a literature review carried out by the Institute of Transport Economics.

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Aggression in traffic, aggressive driver behaviour and its association with road accidents has definitely been put on the agenda in the recent years. One of the major problems concerning aggressive driving behaviour, and the possible association with accidents in traffic, is to define in a clear way what ‘aggressive driving behaviour’ actually is. This difficulty may be a reflection of the variation in definitions of aggression proposed by experts in this field.

Literature review

A review of the literature suggests that three main types of definitions exist. The first defines aggressive driving as direct

physical assaults on other road users. The second focuses on any form of driving behaviour with the intention to injure, harm or frighten other road users physically or psychologically. The last definition puts emphasis on deliberate and wilful driving behaviour that while not intended to harm/frighten other road users shows disregard for their safety and wellbeing.

The literature review concludes that the last definition is the most functional one. This means, however, that aggressive driving behaviour will include acts that commonly are referred to as “reckless driving” or even “active driving” (e.g. failure to give right of way, tailgating). A recommendation is therefore to

NORDIC ROAD & TRANSPORT RESEARCH NO. 3 2004

INSTITUTE OF TRANSPORT ECONOMICS (TØI)

Frustrations generate aggressive behaviour

Studies indicate that the prevalence of aggressive driving is likely to increase during certain traffic situations. The most common ones are situations where drivers’ progress in traffic is slowed down due to unexpected obstructions (e.g. queue outside rush-hour) or unexpected behaviour of other road users (e.g. slow driving when it is difficult to overtake).

At the same time, certain characteristics of the driver seem to increase the likelihood of aggressive driving under such circumstances. Low frustration tolerance, low empathy, mild social deviance and a need for seeking excitement are of particular relevance in this context.

No gender differences

There seems to be no gender difference of importance pertaining to how much irritation and anger drivers experience on the road. However, male drivers report more aggressive acts in traffic than female drivers. This suggests that the irritation and frustration experienced during driving are more likely to result in aggressive driving among male drivers. The propensity to commit aggressive acts in traffic seems to be highest among young drivers, especially young males.

Some studies suggest that characteristics of the vehicle may contribute to aggressive driving. The results indicate

that new cars are driven more aggressively compared to older ones, especially new cars with high engine power, fast acceleration ability and a “sporty” image.

It cannot, however, be ruled out that this result is due to that drivers who anyway would have driven aggressively choose to drive such cars. It is thus uncertain whether it is the car or the driver or a combination of both that contribute to aggressive driving.

Different measures

Measures to reduce aggressive driving have primarily been carried out in the US. Such measures usually include increased police surveillance concerning aggressive driving acts such as tailgating, dangerous overtaking, excessive speeding and red-light running. The use of unmarked police cars seems to be a popular strategy.

The measures are often combined with increased media attention concerning the police efforts to target aggressive drivers.

Other measures include the use of “green numbers”, where road users can dial in the licence number of the driver committing aggressive acts in traffic. There are no formal evaluations of these measures aimed at reducing aggressive driving, but evaluations conducted by the police themselves indicate that such measures may reduce the prevalence of aggressive driving, as well as the number of serious and fatal accidents.

Another measure applied is angermanagement courses for aggressive drivers. Studies show that such courses may be beneficial in order to decrease the irritation experienced when driving, as well as the frequency of aggressive acts in traffic. The effects are, however, measured at a relatively short time after the completion of the course, meaning that the long-term effect of anger-management courses is uncertain.

Happy New Year 2005

Title: Aggressive driving – a literature review.

Author: Pål Ulleberg (plu@toi.no) Series: TØI report 709/2004 Language: Norwegian

NORDIC ROAD & TRANSPORT RESEARCH NO. 3 2004

PHOTO-SERVICE

use the term “reckless driving” instead of “aggressive driving” if this definition is applied. This will make it easier to achieve a common understanding of which types of driver behaviour that are referred to.

Several studies indicate that driving behaviour that is labelled as aggressive or reckless may increase the risk of traffic accidents. The most dominant ones are excessive speeding, tailgating, failure to yield the right of way for other road users and red-light running. At the same time, explicit aggressive acts like rude gesturing, flashing headlights, sustained hornhonking and yelling do not seem to increase the accident risk. However, drivers who behave in such ways are also more likely to conduct other types of aggressive driving behaviour that increases the risk of accidents.

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INSTITUTE OF TRANSPORT ECONOMICS (TØI)

Road Investments in Oslo Did Not Induce New Traffic Major road and transit infrastructure investments in the Oslo region in Norway have been partly financed by a toll ring established in 1990. There are no indications that the road investments themselves have induced new traffic in general in the region. Traffic growth has occurred on major roads, while local roads have experienced unchanged traffic volumes.

The Government has covered 45 per cent of the investments in the period 1990–2001 as planned. However, the last two years the Government share has been decreasing. A fully connected metro system and road lanes reserved for buses have been important and effective measures for public transport.

During the period 1990–2002 traffic growth has been slightly lower than the

national average, in spite of strong growth in factors like population, employment and income. Thus, it is hard to claim that major road investments have induced new traffic in general in the region. Traffic growth has occurred on major roads, while local roads have experienced unchanged traffic volumes. This is in line with the aims of the investment package. The toll ring itself led only to a small reduction in car travel crossing the cordon toll (3–5 %).

In the period there is a slight reduction in travel times during morning rush hours, but no significant change in the afternoon. Increased road capacity has thus counter-balanced the growth in traffic with a small positive margin. Main improvements have occurred along the outer ring road (Ring 3). Delays vary by corridor, western and southern corridor being the worst. Road sections 10–15 km

Increased road capacity in Oslo in the period 1990–2001, partly financed by the toll ring, has counterbalanced the growth in traffic with a small positive margin.

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from the city centre have the largest delays. Freighters regard road accessibility to be improved.

Air pollution levels do not seem to be negatively affected by road investments.

Noise nuisance is reduced where new roads are built as tunnels. Measures to improve the local environment, like traffic management, reinforce environmental effects. Traffic accident risks are reduced, but to a smaller extent than on national level. However, Oslo experienced a larger reduction in persons killed and severe injuries due to traffic accidents than the national average.

The population was rather negative to the toll ring before it opened, but the opposition is reduced over the years. Two thirds of the population are in favour of a new toll ring where a substantial part of generated income is dedicated to public transport. Car travellers passing the toll ring are fairly representative for the population as a whole, but have slightly higher income.

The toll ring has succeeded in putting forward extra effort in infrastructure investments in the Oslo region. The investment plans were not fully developed at the time of decision, giving need for revision and a certain room for flexibility on the way. In the future, if the toll ring is continued, subsidies to public transport should also be included in the scheme. Parking and land use policies and possibilities given by a time differentiated toll should also be evaluated. Less a priori guidance on the use of means should be given. Measures should be chosen according to their cost effectiveness and achievement of specified goals.

Title: Evaluation of Trunk Road Investments in Oslo Author: Jon Inge Lian (jil@toi.no) Series: TØI report 714/2004 Language: Norwegian

NORDIC ROAD & TRANSPORT RESEARCH NO. 3 2004

INSTITUTE OF TRANSPORT ECONOMICS (TĂ˜I)

Increased Penalties Make People Use the Seat Belt During the last 10 years, fixed penalties for traffic law violations have been increased several times in Norway.

Seat belt wearing is found to increase when the fixed penalty for not wearing them increased.

The purpose of this study was to evaluate the effects of these increases on road user compliance with traffic law. The study is confined to speed limit violations and non-wearing of seat belts. These are the only types of violations for which reliable data can be obtained from 1995 (speed) or 1979 (seat belts).

Speed is routinely measured at automatic traffic counting stations operated by the Public Roads Administration. Data from a sample of 34 such stations were used to analyse annual changes from 1995 to 2003 in the percentage of drivers violating speed limits. A tendency was found for the percentage of violations to increase. No effect of the increases in fixed penalties for speeding was found.

Speed is also measured at locations where speed cameras have been installed.

Data from 33 such locations were used in the study. A tendency was found for increased fixed penalties to be associated with a reduction in the percentage of violators. Although this tendency was not statistically significant, it was consistent in all analyses.

These apparently inconsistent findings can probably be explained in terms of differences between speed camera locations and the rest of the road system with respect to the risk of apprehension. When the risk of being apprehended is high, as it is at the speed camera locations, stricter penalties, in the form of higher traffic tickets for offences of a given severity may have a deterrent effect. Making penalties stricter will, on the other hand, not have a similar deterrent effect if the

Seat belt wearing was found to increase when the fixed penalty for not wearing them increased.

risk of apprehension is low, as it is for speeding in general.

Seat belt wearing was found to increase when the fixed penalty for not wearing them increased. The effect of increased fixed penalty was largest in urban areas, where the percentage of violations is higher than in rural areas.

Some models of enforcement suggest that the police will reduce enforcement if penalties are made more severe. This study found no evidence of such a behavioural adaptation by the police.

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The report contains an international comparison of the levels of fixed penalties for traffic violations. These penalties tend to be higher in Norway than in other highly motorised countries.

Title: Effects for increased fixed penalties on road user compliance with traffic law Author: Rune Elvik (re@toi.no) Series: TĂ˜I report 725/2004 Language: Norwegian

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SWEDISH NATIONAL ROAD AND TRANSPORT RESEARCH INSTITUTE (VTI)

With Tiny, Tiny Article written by Michael Höglund, VTI. For more information contact mats.gustafsson@vti.se.

The potentially major consequences of certain particles on human health are keeping researcher Mats Gustafsson at VTI very busy.

Mats Gustafsson is hunting for particles of less than 10 micrometers in size, namely particles that are invisible to the naked eye. In air quality circles these particles are called PM10 or inhalable particles.

VTI has a great interest in particle research because road traffic accounts for approximately 20 per cent – in some places significantly more – of particle emissions in Sweden. The particle emissions occur partly as a result of vehicle exhausts, but particles from wear of road pavements, tyres, brakes and through road service and maintenance i.e. salting and sanding, are very important for PM10.

– It is quite natural that VTI is involved because we have broad competence and partly unique resources in these areas. We also have a well established collaboration with particle researchers at the universities of Lund, Linköping and Stockholm, among others. VTI also has the technical equipment which helps us to generate and study wear particles and we are actively investing in improving our measurement resources, states Mats Gustafsson.

– VTI possess a wide range of competence in the fields of composition and properties of road paving materials, winter and summer road service and the maintenance of paving materials. We and our collaborators also have extensive knowledge regarding the environmental and health aspects related to the area.

– VTI definitely has the capacity to offer qualified action-orientated research, inventory and advice, says Mats Gustafsson.

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The VTI road simulator can be used for generating wear particles.

Stricter requirements from 2005

The link with negative effects on human health has meant that an environmental quality standard for PM10 will come into force 2005. The standard will be reinforced with limits for even smaller particles – PM2,5. This requires municipalities and road service companies to investigate partly whether the limit is being exceeded and partly how the problem can be dealt with. The regulations about the environmental quality standard were introduced at the same time as the environment code which came into effect in 1999. In other words, environmental quality standards are a new control mechanism in Swedish environmental law.

Particles and people’s health

Particles from road traffic can consist of soot and other combustion wastes from vehicle exhausts, rubber particles from tyre wear, and stone particles from the road surfaces etc. The effect of the particles on our health has proven to be depen-

dent to some extent on the size of the particles. The link however is complicated and the chemical composition, surface chemistry, shape and surface structure possibly all have some role to play.

Particles with a diameter of more than 10 micrometers get caught in the nose, mouth and throat and it is suspected that they mainly act as irritants causing coughing for example. Larger particles such as pollen however can trigger off and cause allergic reactions. Particles less than 10 micrometers can, depending on their size, fasten in the respiratory passages, causing respiratory illnesses in various parts of the breathing system. Particles of less than 2.5 micrometers can get as far as the lung alveoli.

The major effects on our health are thought to be caused by particles of less than 2.5 micrometers although coarser particles have also been related to negative health effects.

VTI’s research in the field of particles

– We are researching into the physical and chemical properties of road dust particles

NORDIC ROAD & TRANSPORT RESEARCH NO. 3 2004

SWEDISH NATIONAL ROAD AND TRANSPORT RESEARCH INSTITUTE (VTI)

PHOTO: MATS GUSTAFSSON/VTI

Particles in View

as well as into how toxic they are on human cells. Basically at the moment, we don’t know for sure which properties of the particles can affect human beings and that is what we are trying to find out.

A lot of research is going on in this field, both in Sweden and abroad. One current project is about the dust caused by studded winter tyres and winter sanding on the road surface, which is why many road and street environments in towns and cities do not come up to the environmental goals set for particles that can be inhaled in the local air. Wear material from paving materials is also a significant source of sediment pollution in surface waters near major roads. At the moment it is not clear how and to what extent the different measures taken in road building, service and maintenance can reduce the problems, which is why efforts are needed to clarify all this.

What has been done so far?

VTI has made several investigations into the area of road dust.

– During 2003, we acted as consultants for the County Administration Board in Stockholm working on an action programme for Stockholm’s problem with high concentrations of particles that can be inhaled (PM10), says Mats Gustafsson.

The proposal regarded as the most effective was the one to reduce the use of studded winter tyres because a very large amount of PM10 consists of wear particles from the road surface caused by studded tyres. There were several other proposals focussing solely on road dust in the action programme, such as, binding the dust during periods of extremely high dust concentrations, improvements in road surface materials, and improved road cleaning.

At present a research program, WearTox, is going on at VTI with Lund and Linköping universities supporting with aerosol and health expertise respectively. In the project, particles from the friction between the road surface and the tyres are generated and analysed using VTI’s experimental road simulator. The

NORDIC ROAD & TRANSPORT RESEARCH NO. 3 2004

machine has long been used in wear studies. However the interest in particles has opened up a unique field of research where the road testing machine can generate wear particles from road paving materials. There has been a lot of interest shown in this work due to the low levels of knowledge in this field and the fact that particles are important for the environmental quality standards.

– Experiments have shown that studded winter tyres produce far more PM10 than non-studded winter tyres, but also that a fraction of very small particles are produced (ca 20–40 nm). This fraction is produced when both studded and non-studded tyres are used, but the non-studded winter tyres tend to produce even smaller particles in the wear situation, says Mats Gustafsson.

– We have also shown that different pavements produce very different amounts of PM10 and that they have different toxicological potential in human airway cells.

Uncertainty about effects on our health

There is very little knowledge about which exact properties of the various particles which can cause health problems. A lot of research indicates that the smaller particles are more dangerous, but many studies also indicate that other properties rather than mere size are more important.

Moreover there are studies where large particles have just as bad or even worse effects than small particles. Even though the knowledge of how different particle properties affect health is small yet, we are sure about the connection between inhalable particles and health effects.

– That is why it is important to do active research into which particle properties are really dangerous for our health and at the same time find effective measures to reduce particle contents, says Mats Gustafsson.

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SWEDISH NATIONAL ROAD AND TRANSPORT RESEARCH INSTITUTE (VTI)

VTI-Algorithm Structuring the Austrian Road Network Article specially written for Nordic Road & Transport Research by Fridtjof Thomas, fridtjof.thomas@vti.se, +46 243 736 75.

– At last we can do it! Petra Simanek is pleased with her new ability to generate homogenous road sections for the Austrian road network. For the first time she is now able to automatically identify consecutive parts of the Austrian roads that are similar with respect to rut depth, skid resistance, and longitudinal unevenness as measured by the International Roughness Index (IRI). The tool at her disposal is an implementation of the segmentation algorithm developed at VTI. – We measure the federal roads periodically with a road surface profiler, but until now we haven’t been able to handle the first step in the analysis of the large

amount of data in an automated way, explains Petra Simanek from the Institute for Road Construction and Maintenance at Vienna University of Technology (ISTU). She has been leading the project that has combined the Austrian needs with the statistical approach developed in Sweden and that has resulted in the stand-alone software SAMSRoad.

– I use SAMSRoad in two ways, explains Petra Simanek. SAMSRoad generates the homogeneous sections needed in our pavement management system (PMS), and it can do that fully automatically for all the federal roads in all our counties. But SAMSRoad also allows me to have a look at selected parts of a road: the program allows me to manually change identified homogeneous sections by simply clicking with the mouse on the section borders, and it gives me a neat representation of the entire road in terms of summary measurements computed on the identified sections.

– We felt the need to generate homo-

geneous sections, before summarizing the surface conditions in terms of average rut depth and the like, but we couldn’t find an approach that would give us reasonably reliable results when fully automatically executed, says Alfred Weninger-Vycudil, the architect behind the Austrian PMS at ISTU, describing the problem targeted by SAMSRoad.

– The resulting sections should really be homogeneous with respect to those measurements we actually consider in subsequent optimization procedures within our PMS. Ultimately we want to derive good maintenance plans for our federal roads from this project, and we do collect high quality road surface measurements – so it felt odd not being able to identify sections of a road that are homogeneous with respect to rutting or unevenness.

It was decided at an early stage in the project that the result should be a standalone computer program that can process large amounts of data. Therefore programmer Murat Özcan, who frequently

PHOTO: ANDREAS PFEILER/ISTU.

The SAMSRoad team, from left to right: programmer Murat Özcan, researcher Fridtjof Thomas (VTI), project manager Petra Simanek (ISTU), dean prof.

Johann Litzka (ISTU)), researcher Alfred WeningerVycudil (ISTU).

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NORDIC ROAD & TRANSPORT RESEARCH NO. 3 2004

SWEDISH NATIONAL ROAD AND TRANSPORT RESEARCH INSTITUTE (VTI)

Screen dump showing a SAMSRoad session. The acronym SAMSRoad is derived from Statistical Analysis of Measurement Series on Roads. The upper diagram shows the running length of a road on the horizontal axis and the measured IRI-values of 50 meter long sections on the vertical axis. The bottom diagram shows a representation of the road as mean IRI-values (red lines) and mean plus one standard deviation (green lines). The mode or any user-specified percentile might be displayed instead.

tackles scientific programming problems at ISTU, was brought into the group, and the project was started with a three day meeting in Vienna. Murat Özcan had to constantly translate the wishes from the potential users to feasible software solutions, and stressed the importance of the interface issues.

The algorithm is the part that sets the program apart from other approaches, but it’s the user interface that will determine whether the program is used in the future.

SAMSRoad should be viewed as a routine implemented in a statistical program package, even though it is standalone software that can execute in batch mode and process large data sets fully automatically. The method will work if the measurement series submitted satisfy certain requirements. But it is the user’s responsibility to check whether these requirements are reasonably well met.

SAMSRoad was written in JAVA pro-

gramming language and runs on a variety of computer platforms, including Windowsbased systems, Macintosh, and UNIX.

SAMSRoad is available through ISTU’s website at http://www.istu.tuwien.ac.at.

Related publications: Thomas, F., Weninger-Vycudil, A., and Simanek, P. (2004). Automated Segmentation of Pavement Measurements Based on Bayesian Ideas: Experiences from Austria. Proceedings 6th International Conference on Managing Pavements, 19–24 October 2004, Brisbane, Queensland, Australia. (Paper No. 136.)

Thomas, F. (2003). Statistical Approach to Road Segmentation. Journal of Transportation Engineering, Vol. 129, No. 3, pp. 300–308.

Thomas, F. (2004). Automated Road Segmentation Using a Bayesian Algorithm.

Journal of Transportation Engineering, approved for publication.

Thomas, F. (2004). Generating homogeneous road sections based on surface measurements: available methods. Proceedings 2nd European Pavement Management Conference, Berlin, 21–23 March 2004. Reprint available: http://62.119.60.67/EPiBrowser/Publikationer/S360A.pdf Thomas, F. (2001). Databaserad indelning i homogena sträckor: hur skall metodiken implementeras? I Rapportsammanställning av föredrag vid forskardagarna i Linköping, 10–11 januari 2001, del 4. Statens väg- och transportforskningsinstitut (VTI), Linköping, Sverige. In Swedish.

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SWEDISH NATIONAL ROAD AND TRANSPORT RESEARCH INSTITUTE (VTI)

Designing and Testing a School Transportation Bus Stop viour, e.g. speed and lateral position, according to the traffic situation.

One way to make it safer for children waiting for, entering, or getting off a school bus is to use a bus stop fitted with a dynamic flashing/running light; a light that is activated only when children are present at the bus stop or within a radius of 50 metres of it.

Market analysis

A market analysis of possible systems showed that there was no system in use with dynamic or variable signs at school bus stops, but there was good experience with movable bus stops. Previous studies have also shown that variable running lights in greater numbers, compared to static lights, catch the driver’s attention without causing risky driving behaviour.

This was used as a starting point in the construction of this study. The idea was also to create a system with high acceptance by both children and drivers. In order to achieve such acceptance, a system was created that was activated by radio transmitters and active only when children were present at a radius of 50 metres from the bus stop.

Radio transmitters were used to activate the flashing/running light. The flashing/ running lights were to announce to the school bus driver and other drivers that children were present near bus stop.

Furthermore, it also implied the opposite i.e. when the lights were not activated there were no children present.

A pilot study was conducted aimed at finding a solution that would make it safer for children waiting for, entering or getting off the school bus.

The concept is based on an idea to design a system that guarantees that children are able to wait for the school bus safely and, at the same time, that children will be visible to the school bus driver and other road users, which in turn, hopefully will make them adjust their driving beha-

PHOTO: TORBJÖRN FALKMER/VTI

Promising results

The school transportation bus stop used in the VTI study.

14

In summary, the results show that the bus stop makes drivers reduce their speed.

Comparison of the speeds observed with the drivers’ self reported behaviour showed that the majority of those who claimed to have reduced their speed actually did so.

Moreover, those who claimed not to have reduced their speed, in fact did so. The promising results concerning the speed reduction were followed with equally promising results for the lateral lane position.

Measurements were also made only

with the bus stop and no flashing/running lights in order to find out if drivers increased their speed and reduced the safety distance. The result showed this to be true. This implies that the flashing/ running lights had a positive effect on driving behaviour from a safety perspective.

High acceptance of the system

The acceptance of the system including the radio transmitters was also high. The level of acceptance of the system by the children, the parents and the drivers was high.

– The results from this pilot study show that it is possible to construct a bus stop including a sign with flashing/running lights that is activated automatically using radio transmitters carried by the children. The results, furthermore, show that driving behaviour changed due to this particular bus stop system. The average speed decreased and the safety distances to the bus stop increased. Moreover, there was an acceptance of the system by the children, parents and the drivers. The local community’s demand for a safety solution for children combined with these positive results leads us to the conclusion that we would like to recommend a system like this. It would make it safer for children while waiting for and entering a school bus or getting off it on their way home from school, say the researchers who performed the study at VTI.

Title: Designing and Testing of a School Transportation Bus Stop Authors: Anna Anund, Torbjörn Falkmer and Helena Hellsten Series: VTI rapport 494 Language: Swedish with English summary The report is also available as a pdf file on www.vti.se/ Publications.

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SWEDISH NATIONAL ROAD AND TRANSPORT RESEARCH INSTITUTE (VTI)

Driving when Tired – from the Drivers’ Point of View Drivers are aware of their own signals that indicate fatigue while driving.

However, they underestimate the risk of driving when tired and overestimate their ability to master the situation.

Dedicated information to drivers seems to be a potential countermeasure. Such information should aim at improving the drivers’ awareness of the risks of driving when fatigued and provide information about relevant countermeasures.

Young drivers – at high risk

The knowledge provided by the present study could be used to formulate guidelines for potential measures aimed at reducing the number of fatigue-related accidents. Special attention was paid to which information could be provided to drivers.

A questionnaire was drawn up on the basis of discussions with three focus groups; one with young drivers, one with professional drivers and one with commuters, and sent out to a random sample of 3,000 car owners in Sweden.

The results were analysed with respect to drivers’ characteristics e.g. age, gender, professional drivers and shift work.

The report focuses on the differences in drivers’ views on how various factors work as driver fatigue “triggers” and how to fight sleepiness and stay awake.

The results indicated that there were

Experience is a good teacher PHOTO: THOR BALKHED/BILDAMEDIA

In order to reduce the number of fatiguerelated accidents and to identify countermeasures that will be widely accepted by drivers, it is necessary to consider the drivers’ point of view. Understanding drivers’ experiences and conceptions of the dangers due to driver fatigue is necessary when trying to find effective countermeasures that stand a good chance of being accepted by the drivers.

sensation of fatigue. Secondly the driver has to be motivated to take some action, to know what countermeasures can have a lasting effect, and finally be able to act accordingly. However, the major goal is to reduce the risk of a driver, who is likely to fall asleep while driving, actually getting behind the wheel and driving.

differences between groups of drivers regarding health, sleeping habits, impression of different fatigue-inducing factors and countermeasure preferences. Young drivers and professional drivers seemed to be the drivers that are more at risk of fatigue-related accidents.

Information and control measures

Information intended to convince drivers to take action could be provided at different stages, ranging from pre-trip strategic information to last-minute evasive control measures. It seems reasonable that strategic information could have a great influence on reducing the number of fatigued drivers on our roads. Strategic information should endeavour to make the driver avoid driving when there is a greater risk of getting sleepy while driving.

Tactical information should focus on how to manage sleepiness while driving, e.g. to stop driving and have a break. The process of avoiding fatigue-related accidents, from the drivers’ point of view, could be described in several steps. First of all, the driver has to be aware of the

NORDIC ROAD & TRANSPORT RESEARCH NO. 3 2004

The results indicated that the drivers were aware of the sensation of fatigue.

Furthermore, the results indicated that drivers underestimated the risk of driving while fatigued and overestimated their own ability to be able to manage the situation. The use of countermeasures differed between the driver groups. Young drivers seem to have little knowledge concerning long lasting countermeasures. They turned on the radio or increased the volume of the radio or asked passengers to talk to them. Older drivers seemed to be more in favour of taking a break and having a nap.

In conclusion, the results from this study support the idea that dedicated information about the risks associated with driver fatigue and possible long lasting countermeasures should be developed and provided. The results also underline that this information should be specially addressed to both young and professional drivers.

Information can be a relevant countermeasure in the effort to reduce the number of fatigue-related accidents.

Title: Driving when tired– from the drivers’ point of view Authors: Anna Anund, Göran Kecklund and Björn Peters Series: VTI rapport 498 Language: Swedish with English summary The report is also available as a pdf file on www.vti.se/ Publications.

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NORWEGIAN PUBLIC ROADS ADMINISTRATION (NPRA)

Sand, Salt and Hot Water in Winter Road Maintenance Article written by Torgeir Vaa, SINTEF (torgeir.vaa@sintef.no)and Roar Støtterud, Centre for Road and Traffic Technology, Trondheim (roar.stotterud@vegvesen.no).

Translated and edited by Thorbjørn Chr. Risan, Centre for Road and Traffic Technology, Trondheim (thorbjorn.risan@vegvesen.no).

Recognising that there was a need for increased knowledge of all types of friction measurements, the Norwegian Public Roads Administration started a research project in 1997 with focus on winter road maintenance. The goals for the project were, among others, a) to come up with optimal methods that can be of practical use and b) come up with the type and amount of salt and sand to be used during various conditions. Besides studying different sanding and salting methods, the project has also dealt with different ways of applying abrasives.

The first truck based on the warm wetted sand principle in Norway was called Friction Maker. This truck, which was tested the first time in the 1998/1999 winter season, was a reconstructed truck spreader with a dropside body. A water tank with a capacity of 2.5 m3 and a heater with a water pump were mounted onto the lorry body. The first prototype was provided with a spreader towed behind the dropside body. Field trials during the winter seasons 1998/1999 and 1999/2000 led to the conclusion that further development of the method should be based on a spreader with a spinner, heater system for water and material box and transport of the sand ensuring workable methods for handling the sand. There have been great changes in the spreader concept and heater system during the project period.

In the newest concept, the heater system 16

The first Norwegian prototype, Friction Maker, with a spreader towed behind the dropside body, and a newer construction based on a spreader with a spinner.

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NORWEGIAN PUBLIC ROADS ADMINISTRATION (NPRA)

and water tanks are separated. The new spreader type in combination with a spinner can be used both for spreading sand and salt with or without adding liquid.

Description and method

The warm wetted sand method is based on adding hot water to the sand so that the sand particles are covered with a film of water. When the sand sprinkled with hot water leaves the spreader and lands on the frozen surface of the road, the film of water has a short melting effect. This mixture of sand and water freezes to the surface as lumps and gives the road a kind of sandpaper texture.

The most significant factors in the warm wetted sand method are the quality of the sand, amount of water, the spreading speed and the water temperature. The sand should be of a specified quality corresponding to a 0–4 mm gradation.

Hot water means that the water temperature is 90–95ºC. The amount of water in the mixture of sand and water is approximately 30 weight percentage, and the normal dosage of sand used is equivalent to 200 grams/m2 as an average. In the winter seasons 2000/2001 to 2002/2003 focus was given to developing the spreader technique and testing new spreaders in addition also to gain experience with the new method in daily operations. The testing has been conducted as scientific studies.

Testing of the method

The effect was measured in two ways by: 1) how much the friction was improved and 2) how long the achieved improvement lasted. Two different friction measuring devices (called OSCAR and ROAR) were used to determine the friction level. Both devices are continuous measuring types with a variable slip test wheel. The friction measurements were done until the friction level with the most durable effect was back to its pre-test state or the trial was disrupted by change in weather conditions. The evaluation system also included the possibility of simultaneous video images every 20 meters together with the friction measurements. Road weather information was gathered and the number of vehicles counted. Two comprehensive scientific

Detailed result of the warm wetted sand method.

studies were carried out through the winter season 2000/2001. These field studies comprised of 35 road sections strewn in each direction with a length of 1 km.

The results from one of the trials with different sanding methods on E136 during the 2000/2001 winter season, showed that the method used in combination with a spinner type spreader gave almost as good results as the system combined with a roller distributor even though the spreader pictures are quite different. The traffic volume on this road was 1,200 vehicles per day including approximately 30 per cent heavy vehicles. The second last friction measurement was made 5 days after sanding. Even if much of the sand

NORDIC ROAD & TRANSPORT RESEARCH NO. 3 2004

had been worn away there was still enough sand on the surface to raise the friction above the background level.

To evaluate the different sanding methods, a thermo camera was used in most of the scientific tests. The camera was an Inframetrics SC1000 that operates in temperatures from 10 to +2,000 degrees centigrade. The sensitivity is 0.1ºC. For picture analysis, the emissivity for a mixture of sand and water is set to 0.94.

Tests show that the temperature loss increases rapidly with increasing spreader width. Even with the spreader set to 4 metres, the drop in temperature will influence on the effects with regards to friction improvement. Possible differen17

NORWEGIAN PUBLIC ROADS ADMINISTRATION (NPRA)

ces in spreader performance with regards to the temperature of the material leaving the spinner can therefore result in different friction improvement gains.

There were found only small variations between the different trucks used in the experiments except for one of them which probably can be explained by a difference in the spreader concept. There was however no significant difference between the first Norwegian prototype, Friction Maker, and the trucks with a spinner when it came to the rise in the friction level.

Prewetted salt with hot water

Through developing sanding equipment for spreading warm wetted sand, the time has now come to develop a complete new method by adding hot water to salt.

During the winter season 2003/2004 a wet sand unit, which was used for tests with prewetted salt together with hot water, was placed at Lyngdal garage in southern Norway.

In addition to be a considerable contribution to increase the knowledge of alternative methods, these tests also were interesting because of possible increased utilisation of the warm wetted sand unit.

The purpose of the test was to find out if the method of prewetted salt with hot water could be an alternative to the traditional way of wetting salt by adding salt solution.

The result of the tests, which were carried out during the weeks 2, 5 and 9 in 2004, showed clearly that there is a difference in favour of the new method with use of warm water compared with traditional use of salt by adding salt solution as liquid. (Same dosage was used during the tests.) This is related both to a more rapid effect and also a higher level of friction. Not until 2,5 hours after the application, the effect of the two methods was approaching. The results also indicated that the total quantity of salt was reduced by replacing salt solution with water. If these results are maintained in further tests, it means that we can obtain the same effect on friction development by a less dosage of salt with the new method compared with traditional use of salt.

Tests carried out with preventive salting showed that there was no significant dif18

Test field strewn with warm wetted sand. The first picture is taken 18th January 2001, the second 22nd January.

ference between the two methods when it came to the quantity of residual salt, i.e. there was the same quantity of salt in the roadway with the new method as with traditional wetting with salt solution.

Consequently the new method also will be suitable for preventive measures.

The completion of the tests confirms that prewetted salt with hot water is an alternative method of great interest to follow up. There has been no detection of negative aspects of the method.

Nevertheless it is important to make further tests to have more experience with the method and to give answers to the current problems which have been raised among other factors in relation to how much the chemical process accelerates, exact quantity of fluid, how much the quantity of salt can be reduced and the consequences for traffic and temperature limits as regards salting.

NORDIC ROAD & TRANSPORT RESEARCH NO. 3 2004

NORWEGIAN PUBLIC ROADS ADMINISTRATION (NPRA)

Toll Financing – How to Reduce the Operating Costs?

The picture is from the new toll ring in the city of Bergen, which was opened 1st of February this year. The toll station is fully automatic, has few lanes, no toll booths and a relatively high OBU share (On Board Units). Our findings suggest solutions like this.

Article written by Erik Amdal (erik.amdal@vegvesen.no), Morten Welde (morten.welde@vegvesen.no), Norwegian Public Roads Administration.

motorway network as well.

The net revenues from toll financing annually make up between 25 and 35 per cent of the annual budgets for road construction. Norwegian motorists spend averagely

Toll financing in Norway has been used to finance new roads as a supplement to public funds for more than 70 years. In total over 100 projects have been financed by tolls and only one has ever been declared bankrupt.

Tolls have traditionally been used to finance bridges and tunnels to supersede ferry connections, but since the 1980s the number of and the type of projects financed by tolls have increased considerably.

Today there are 47 projects and the number of projects is increasing. There are 7 toll cordons in operation and although fixed link projects still make up the bulk of the total number of projects, there are plans to use tolls to finance larger parts of the

175 euros per vehicle per year on tolls.

The use of technology plays an important part in the toll collection. Since the early 1990s an increasing proportion of the tolls have been collected using

Number of toll projects in Norway 1932 – 2004

The figure illustrates the development in the number of toll projects.

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NORWEGIAN PUBLIC ROADS ADMINISTRATION (NPRA)

electronic fee collection (EFC), which means that the motorists pay the tolls using a tag attached to the windscreen of their car. The AutoPASS tag is based on an open standard owned by the Norwegian Public Roads Administration (NPRA) and used in all new toll projects.

In spite of the extensive experience in toll financing, little research has been done to examine solutions for minimising the operating costs and hence maximising the social surplus of each project.

The NPRA has therefore carried out a study to establish a cost function that can identify the main cost drivers in toll projects. The results of the study are presented here.

companies were asked directly. The (pooled) data set consists of data from 24 toll companies over the years 1998–2003 and includes 5 toll rings, 5 highway projects and 14 fixed link projects. Only observations from years where there were no significant changes in the operations were included.

Since the data collected refer to different years, we needed to establish a common time reference. This was done by adjusting the data to 2003 price levels.

The average operating costs vary considerably among the toll companies.

Table 1 gives the summary statistics for the average costs (all figures are in Norwegian kroner):

The model and data

Statistics A model with variables covering all characteristics of toll projects can ease the planning of new toll projects by providing more precise estimates of the net revenues and reducing the risk of financial default. Estimating the operating costs can be done by estimating a cost function that shows how costs vary with the factors that influence them.

Based on a log-linear functional form we estimated a cost function covering the following variables: • traffic: total number of paying vehicles (in thousands) • size: total debts by the end of each year (in millions) • lanes: number of lanes in the toll station(-s) • age: number of years since the opening of the project • OBU: percentage of vehicles using On Board Units.

In addition, we included two dummy variables: • passenger charging: passenger charging or not • toll cordon: toll cordon or not.

The average operating costs, measured as the operating costs per charged vehicle in each project, were used as the dependent variable.

The data was obtained from the NPRA’s database containing data from the annual financial statements compiled by the toll companies responsible for the toll projects. In the cases were information was incomplete or missing, the toll 20

No. of cases Mean Standard deviation Median Minimum Maximum

113 6.89 7.16 5.84 0.78 39.79

Table 1: Summary statistics - average costs.

The large discrepancy between the observations might be an indication that the performance of the toll companies, their efficiency, varies as well. That is, however, not the focus of this study.

On the other hand, large cost differences might have consequences for the viability of the projects. If we assume that the total costs of toll financing consists of the operating costs and the social costs of diverted traffic, the viability of the projects will depend heavily on the costs of collecting the tolls. The cost-/revenue ratio in Norwegian toll projects varies between 5 and 35 per cent – a clear indication that some projects should rather have been financed using public funds (or indeed; not been realized at all). Thus, if we can reduce the operating costs of toll projects, this can be a major contribution to increasing the viability of Norwegian road projects.

Results

The estimation gave some interesting findings. A simplified version of the regression results are presented in table 2:

Parameter Traffic

Elasticity -1,278

Size

0,049

Lanes

0,731

Age

-3,2

OBU

-0,9

Toll cordon Passenger charging

-0,859 0,301

Table 2: Estimation results.

Our findings suggest that there are strong scale economies present in the relationship between average costs and traffic, at least over the traffic levels experienced in Norwegian toll projects.

The larger the project, the lower the operating costs.

The size of the projects, measured in debt by the end of each year, influence costs negatively. That is, a 1 per cent increase in debts (in millions) will increase average costs by 0.049 per cent.

We find that the number of lanes is the most important cost driver in toll projects.

This is not surprising. Tolling equipment such as toll booths, coin machines and other road side equipment are expensive both to purchase and to maintain, and by increasing the number of lanes in a toll station, the operating costs will increase.

When the number of lanes increases by 1 per cent, average operating costs increase by 0.73 per cent. Hence, if a project in which tolls are collected in 10 lanes adds one extra lane to its toll station(-s), the operating costs per vehicle are likely to increase with 7.3 per cent, assuming all other variables remain unchanged.

The age component seems to be negative but it is not statistically significant at the 5 per cent level (although at the 10 per cent level). We can draw the conclusion that the toll companies’ operating costs decrease by 3.2 per cent per year in real terms but further studies are necessary to determine whether the toll companies are able to utilize any economies of experience to improve the efficiency of their operations.

The most important technological innovation in Norwegian toll collection is the introduction of electronic fee collec-

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NORWEGIAN PUBLIC ROADS ADMINISTRATION (NPRA)

tion and especially the development of the AutoPASS-standards for tags and central system. This has reduced the need for cash handling and staff. Therefore, as the percentage of vehicles using OBUs increases with one percentage point the average operating costs will decrease by 0.9 per cent. Thus, if a project manages to increase its OBU-share from 60 to 80 per cent, operating costs should decrease 18 per cent.

The dummy variable for toll cordons is negative. This means that we can conclude that toll cordons have 86 per

other studies which have found the welfare effects from introducing tolls to be lower on urban motorways than on rural roads. The cost of toll financing is lower than public finance when the traffic level is high and the toll is low. From a social perspective it is also worth noticing that it is usually easier to provide alternative modes of transportation in urban than in rural areas and that the elasticity of high tolls is higher than the elasticity of low tolls. This may have implications for public acceptance as well.

cent lower average costs than other toll projects. One explanation for this remarkably high estimate is benefits from scale economics and extensive use of modern technology, a characteristic of all Norwegian toll cordons.

After the introduction of the AutoPASS-technology few, if any, new projects will be based on passenger charging.

Given the huge cost disadvantage of the toll companies that are charging passengers as well as vehicles – 30 per cent higher costs than other projects, the practice of passenger charging should be abolished as soon as possible. Considering the usually very low traffic levels in these projects, one must also consider whether other types of financing such as shadow tolls or public funds are more suitable in these, usually fixed link projects.

This is similar to the conclusions in

Recommendations for the future

Our findings suggest that the design and organisation of the toll collection is crucial for minimising the operating costs. As both the average costs and the cost-/revenue ratio between the toll companies vary considerably, there should be some potential for cost reductions if the toll collection in existing projects is redesigned and if the planning of new road projects increases its focus on the toll systems. A rethink is needed in the planning of new toll projects in order to focus on more cost efficient solutions, which are available already.

The key characteristics for minimising the operating costs are therefore as follows: • high traffic levels • few lanes with no toll booths and coin machines

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• EFC and a high OBU share • tolling in urban rather than rural areas • no passenger charging.

The project categories that most successfully have managed to combine these factors in order to keep costs at a minimum are the toll cordons. Both the traffic levels and the OBU share are high in these projects. The extremely high cost of land acquisition in urban areas have resulted in a greater focus on keeping the number of lanes in toll cordons at a minimum as well. This has encouraged new technological solutions such as the fully automatic toll stations that were implemented in Bergen and Tønsberg in February 2004. These toll stations eliminate the need for coin machines and use only as many lanes as the traffic flow requires. Motorists pay through the tag on their windscreen. Those without tags will have their number plate photographed and later invoiced by mail. We would, however, warn against using new technology such as this to promote some notion of fairness through increasing the number of toll stations to prevent motorists who only travel a short distance from paying too much. There have been discussions in Norway whether one should finance larger parts of the motorway network using a number of toll stations, for example for every 10 kilometres. This might be beneficial for public acceptance but if the objective is to keep operating costs at a minimum, other solutions based on the same technology but with less focus on fairness and more on efficiency, should be considered.

The Norwegian experience suggests that low operating costs are feasible if focus is on minimising these. Although average operating costs per vehicle of 0.7–0.8 kroner and cost-/revenue ratios of 5–8 pst. are internationally highly competitive, the NPRA is planning to increase its focus on operating costs in the years ahead. The current large cost differences between the toll companies are unacceptable. As new and improved technology is introduced, and the legal and organisational framework of toll financing is revised, we can hopefully improve the cost efficiency of Norwegian toll financing in the future.

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DANISH ROAD DIRECTORATE (DRD)

The Traffic Information Centre Seen in an International Perspective Article specially written for Nordic Road & Transport Research by Bente Iversen (bi@vd.dk, tel. + 45 33 41 34 21), M.A., Head of Road and Traffic Information.

Traditionally, National Road Administrations across the world have focused on road construction and maintenance. The latest tendencies, however, are more focused on conducting traffic efficiently. What does it mean and how is it achieved? And how are things developing in Denmark?

Danes continue to buy more vehicles.

The Danish road system, however, is not keeping pace with vehicle ownership.

Consequently, traffic flows continue to grow at rates that cannot be sustained by capacity increases from construction, especially around the larger cities.

Obviously, Denmark is not alone in this matter. The situation is the same all over Europe. Saturation point has been reached around cities such as London and Paris which have required alternative and in some cases radical solutions.

From road to management

For many years and rightly so, European Road Administrations have put their efforts into road extensions, maintenance and improvements of the physical infrastructure – the actual road network.

For several reasons, it is no longer possible to keep up the ‘capacity increases’ at the pace of the growing traffic flows. The ‘physical space’ is not the only factor to be taken into consideration; today financial and environmental consi-

Traffic Information Centre (TrafikInformationsCenter), T. I. C., at the Danish Road Directorate.

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NORDIC ROAD & TRANSPORT RESEACH NO. 3 2004

DANISH ROAD DIRECTORATE (DRD)

ITS – a step in the right direction

Traffic management can take several different forms, from a stationary sign warning about a queue, to a traffic announcement on the radio, to more advanced, dynamic, electronic information systems that are centrally controlled.

ITS, Intelligent Transport Systems – such as road sensors and electrical signposting, which warn and inform roadusers on the spot about e.g. queues or travel time to the centre of the city – are a step in the right direction but are only part of the solution.

ITS, however, only solves a limited part of the mission – even when connected to advanced navigation systems. To arrive safely and without delay requires coordination and a far more comprehensive gathering process. This is where National Road Administrations become important.

The obvious centre

The Traffic Information Centre, T.I.C., is the Danish Road Directorate’s traffic management centre – and has been for several years. As an independent, public authority the T.I.C. is the natural centre of all necessary information about traffic and the road conditions.

T.I.C.’s integrity and ability to survey the roads is due to a wide range of different sources.

These sources include the drivers themselves – today more than 5,000 private and professional drivers are listed as the Danish Road Directorate’s RoadReporters. Furthermore, T.I.C. employs a wide variety of ITS, and cooperates with rescue forces, police and other roadauthorities.

Simultaneously, T.I.C. verifies the received data before it is passed on as valid, user-friendly nationwide information. The media that T.I.C. uses covers a broad spectrum; e.g. internet, teletext,

radio, electronic devices placed in the vehicles and broadcasting news on TV. Traffic management in the future

Today effective traffic management primarily means information. T.I.C. and its media partners make sure that the roadusers receive information about e.g. traffic jams, accidents, slippery roads, ghost drivers or when a road is closed to traffic etc.

Due to the change from ‘Intelligent Transport Systems’ to ‘Intelligent Transport Services’, the international Road Administrations will more directly and actively be able to undertake the role as coordinating operative traffic manager in the future, e.g. by opening or closing a lane, by temporarily diverting traffic into the emergency lane – as it is done in England during rush hour – or by recommending inter-modal routes, i.e. routes involving several means of transport, when car and public transportation are combined based on a knowledge on how traffic is at the moment.

Traffic management has to be an integrated part of any kind of effort when a traffic accident or bad weather etc. occurs, because the socio-economic consequences of disrupted traffic flows are far-reaching.

It is therefore incumbent on National Road Administrations to manage the entire process, collecting and disseminating ‘pre-trip’ and ‘on-trip’ information together with the effective management of the available transport infrastructure.

The way forward is clear: traffic management will be of great significance in the future. In other words, traffic management will get closer to reality, to the road and the individual driver.

The gains to society as a whole – an improved traffic flow on one of our most important arterial roads, the motorway – will be significant. This implies that police, emergency services, Public Transport Operators and Road Authorities will pool their resources and efforts to improve this vital function. This is to be discussed in Denmark.

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Visit our web site: www.vti.se/nordic

PHOTO: JOHNNY DAHLGREN

derations are equally crucial.

Alternatively, or perhaps supplementary to a new infrastructure, traffic management comes into play; it ensures that traffic is effectively conducted and thereby we obtain a more useful utilisation of the existing road system.

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DANISH ROAD DIRECTORATE (DRD)

Recycling in Road Construction Has Been Upgraded – New rules for crushed concrete, crushed bricks, crushed asphalt and MSWI bottom ash as road construction materials

Article written by Knud A. Pihl (kap@vd.dk) and Ole Milvang-Jensen (omj@vd.dk), Danish Road Directorate, Danish Road Institute.

The Danish Road Institute has published four new Tender & Construction Precepts for materials which can be recycled – in accordance with new European standards. They apply to materials which can be used for unbound basecourses (crushed concrete, crushed bricks and crushed asphalt) and for Municipal Waste Incinerator Ash (MSWI bottom ash), which can be used as subbase.

At present there is special focus on the new European product standards for 24

sand, stone and gravel. These standards apply in principle to all materials, which are used in road construction, also materials which can be recycled, such as ash, crushed building demolition materials and reclaimed asphalt pavements.

The Danish Road Institute has distributed knowledge about recycling of road materials and other materials for use in road construction for a long time. The possibilities are described in reports, articles and some uses are presented in Road Standards. This applies for those materials, which in Denmark are used as unbound basecourse (demolition materials: crushed concrete, crushed bricks and crushed asphalt) and for MSWI bottom ash which is used as subbase.

Now four new reports have been published, where current European standards are incorporated.

Alternatives to granular subbase material

In Danish road construction it is common to construct a road from the bottom with subbase material, followed by an unbound layer of granular base material, basecourses of asphalt and a wearing course of asphaltic material on the top.

The subbase course normally consists of non-graded sand and gravel material. The basecourse normally consists of granular, well-graded sand and gravel material.

Crushed concrete and bricks from demolition and reclaimed crushed asphalt materials can be equally good alternatives to traditional material as basecourse.

There are conditions (delivery condition) for the produced, recycled materials, which are put up for sale, in the same way that there are conditions for traditional sand and gravel materials.

NORDIC ROAD & TRANSPORT RESEACH NO. 3 2004

DANISH ROAD DIRECTORATE (DRD)

Crushed concrete can replace granular unbound base material for all types of roads. Crushed concrete is a good material, which can be superior to unbound granular base material. There are in principle 3 classes: High quality called Class A, which has a higher bearing capacity than granular base material (an E-modulus of 400 MPa compared to 300 MPa), so there is some saving in the other layers in the road construction. Class B is equal to the bearing capacity of granular base material.

Finally there is Class C, which is a little poorer in quality than traditional granular base material.

Crushed asphalt is a correspondingly good material, which can be equated to unbound base material for use in all

levels from heavily trafficked roads to minor roads and footpaths.

Crushed bricks is a useable material as replacement for granular unbound base material on roads, paths and squares with limited traffic – up to 10 lorries in both directions per day. The available amounts of crushed brick are limited.

well as a traditional good subbase of sand and gravel materials. There are certain limitations in the use of MSWI bottom ash.

Firstly, the ash should not be used on heavily trafficked roads (i.e. roads with more than 400 lorries per day in total in both directions). Secondly, if the subgrade is water exposed, there are also certain restrictions.

Environmental regulations

Ordinary environmental and work regulations apply for construction work.

Particularly for MSWI bottom ash, there may be difficulties in obtaining environmental permissions due to ground water interests in the area, where the road, path or square should be constructed.

Local administrations can use alternative materials with advantage

Major road constructions require large amounts of material. This also applies to a number of the alternative materials mentioned above, which are not available in large amounts. This makes such deliveries impossible. Even though several of

the mentioned materials could be used for construction of heavily trafficked roads, it can in practice be difficult to obtain them, when necessary.

Alternative materials can therefore be used most advantageously for smaller new constructions and since local administrations are in charge of smaller constructions, this seems a good possibility to use crushed concrete, bricks and asphalt as an alternative in granular unbound base. Prices are controlled by market economy, but in general alternative recycled materials are cheaper than traditional materials. In Denmark, local administrations have carried out or have planned constructions with use of recycled materials.

An alternative to traditional subbase material

MSWI bottom ash can often replace sand and gravel materials, which usually are used as subbase material.

MSWI bottom ash has a slightly lesser bearing capacity and does not drain as

Electronic versions of the Danish reports can be found on: http://www.vejdirektoratet.dk/publikationer/VIrap133/index.htm http://www.vejdirektoratet.dk/publikationer/VIrap132/index.htm http://www.vejdirektoratet.dk/publikationer/VIrap131/index.htm http://www.vejdirektoratet.dk/publikationer/VIrap130/index.htm

NORDIC ROAD & TRANSPORT RESEACH NO. 3 2004

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DANISH ROAD DIRECTORATE (DRD)

Noise from Road Humps This article is specially written for Nordic Road & Transport Research by Senior Researcher Hans Bendtsen, Road Directorate, Danish Road Institute. Email: hbe@vd.dk, phone: +45 46 30 70 00.

Road humps are used as a tool to reduce speed and improve traffic safety.

Humps are sometimes used on urban arterial streets with through traffic. In some cases the neighbours have complained about the noise.

In this project these problems were studied using an interdisciplinary approach. The following hypotheses have been set up: 1) On roads with humps the noise is generally reduced because of speed reductions 2) There is a slight increase in noise just before and after the humps, because vehicles, especially trucks, brake and accelerate as they pass the humps.

Eight test sections

Eight road sections with two to nine humps have been selected for the project (see Table 1). The introduction of humps has reduced the speed by five to fourteen km/h. Roads designed for four different speeds were included (30, 40, 50, and 60 km/h). The results are shown separately for these four classes. All the humps are designed as so called "circle humps" where the cross section of the hump in the direction of the road describes a section Road section Road-30 Road-40-1 Road-40-2 Road-40-3 Road-50-1 Road-50-2 Road-50-3 Road-60

The noise measured (as SEL) for mixed traffic (80/10/9/1). The levels "before" the humps were constructed have been predicted.

of the surface of a circle. All the humps more or less fulfil the official Danish requirements for design of humps, and they are representative for newer Danish humps.

It has been important to ensure equal conditions on the selected road sections.

The pavements of the road sections and the humps are dense graded asphalt concrete or surfaces with a similar surface structure. The noise is measured in free field conditions. There are no reflections from buildings or fences. The measurements have been normalised to a road surface temperature of 20째 C. The only variable parameters defining the noise are believed to be differences in speed and driving pattern.

It has not been possible to carry out a

before-and-after study, since the road humps were already constructed when the project was started. Instead, three different measuring positions have been selected on each road section: 1) A position just in the middle of a road hump to represent the noise generated by vehicles passing the humps (termed "hump") 2) A position 10 m before/after the same hump, to represent the noise generated by vehicles braking (decelerating) before or accelerating after the hump (termed "10 m before") 3) A position situated in the middle of a road segment between two humps, to represent the noise generated by vehicles cruising at more or less constant speed (termed "middle").

Design speed

Length of section

Number of humps

Average distance between humps

Speed before humps

Speed with hump

30 km/h 40 km/h 40 km/h 40 km/h 50 km/h 50 km/h 50 km/h 60 km/h

255 m 400 m 631 m 361 m 872 m 1563 m 2219 m 1037 m

2 4 4 3 4 6 9 4

127 m 120 m 147 m 123 m 249 m 274 m 252 m 281 m

Unknown Unknown Unknown 52 km/h 52 km/h 61 km/h 59 km/h 66 km/h

33 km/h 32 km/h 33 km/h 38 km/h 47 km/h 50 km/h 52 km/h 55 km/h

Table 1: The road sections included in the project. The "speed before humps" was measured before the construction of humps.

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NORDIC ROAD & TRANSPORT RESEACH NO. 3 2004

DANISH ROAD DIRECTORATE (DRD)

The microphone height was 1.2 m above ground, and all data has been normalised to a distance of 10 m from the road centre line. The Statistical Pass-By Method was used for the measurements.

The vehicles were divided into four categories: passenger cars, vans, trucks with two axles and trucks with more than two axles. 40 to 334 vehicles were included at each position. For each vehicle, the noise (SEL) and the maximum noise (LAFmax) in octave bands and speed were measured and recorded in a database. The noise has been predicted for mixed traffic with 80 per cent passenger cars, 10 per cent vans, 9 per cent trucks with two axles and 1 per cent trucks with more than two axles (80/10/9/1).

Speed category Annoyed or very annoyed Very annoyed Near hump Far from hump Near hump Far from hump 30 km/h 40 km/h 50 km/h 60 km/h

25 % 20 % 69 % 43 %

58 % 11 % 53 % 13 %

8% 5% 32 % 14 %

9% 0% 7% 0%

Table 2: The main results of the questionnaire survey. Percentage of people answering ‘yes’ to the question: "If you hear road traffic noise, is it annoying when you are inside your home with the windows closed?"

Driving pattern and results

Driving patterns have been registered using a measuring vehicle following randomly chosen vehicles. Driven distance and speed have been registered every second.

The average driving patterns for passenger cars are shown in Figure 1. There is a tendency towards a smoother driving pattern when the design speed of the road increases.

The main results can be seen in Figure 2. The speed (see Table 1) and the noise have been reduced after the introduction of humps. In the "middle" section, the reductions were around 1 dB. At the humps, the highest reductions of 2 to 4 dB are seen. On low speed roads (30 and 40 km/h), the noise tends to be 2 to 4 dB higher 10 meters from the humps than at the humps. This must be caused by acceleration. The same tendencies are seen for all four vehicle categories. Looking at the maximum noise, the same picture is seen.

Social survey and conclusion

A questionnaire has been designed to study the reaction to noise by the people living next to the roads included in the study. All households in the first row along the roads have been presented with a questionnaire. The households have been divided into subgroups; those living close to the road humps (at a maximum distance of 20–30 m from a hump), and those living at a longer distance from the humps. The general reply rate was 78 per

Figure 1.

Figure 2.

cent. The results can be seen in Table 2.

The general tendency shows a higher number of annoyed persons close to the road humps than in between the humps.

On the 30 km/h road, the result is opposite.

The traffic volume and the noise are not the same in the different road categories.

This is likely to be the reason for the big variation in degree of annoyance between the different speed groups.

The first hypothesis is confirmed, as the noise is generally reduced by 1 to 4 dB after construction of humps. The second hypothesis is also confirmed, as the noise is 0 to 4 dB higher 10 m before

NORDIC ROAD & TRANSPORT RESEACH NO. 3 2004

the humps than at the humps. Even though the noise is reduced, people living very close to the humps tend to be more annoyed than people living between humps. Therefore it must be recommended to avoid humps too close to houses.

This article is based on the report “Støj fra bump” (Noise from humps, in Danish with an English summary) by Hans Bendtsen and Lars Ellebjerg Larsen. Report no. 2, 2001 from the Danish Transport Research Institute (can be seen on www.dtf.dk).

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Annotated reports from Technical Research Centre of Finland (VTT), Building and Transport

Operational Model for Railway Incident Management The aim of the project was to define an operational model for railway incident management. The operational model will act as a guide for the further development of incident management at a time when the railway sector is faced with major changes.

The most important factors changing railway incident management are the increase in the number of railway companies and maintenance providers for the railway network and its equipment.

These and a number of other minor factors make it necessary to renew the operational model and the way in which incident management is organised. However this has to be done at the same time as maintaining the parts of the present system which run satisfactorily.

The operational model for railway incident management describes the tasks of authorities, railway companies, network constructors and other relevant parties in different incident management situations. The essential parts of the operational model are: joint planning of incident management, incident management of the situations that are known in advance, real time incident management and

analysis and post incident reporting.

Making the new operational model a reality requires establishing a new kind of organisation for incident management.

An independent Traffic Management Centre is needed to carry out incident management tasks. However incident management is only one of the tasks for the future Traffic Management Centre.

Title: Operational Model for Railway Incident Management Authors: Jukka Lähesmaa and Juha Levo, SysOpen, Raine Hautala and Kirsi Pajunen, VTT Building and TransportSeries: Fits reports 46/2004 Language: Finnish with English abstract http://www.vtt.fi/rte/projects/fits/ju lkaisut/hanke4/fits46_2004.pdf

Drivers’ Views on the Frequency and Tolerance of Speed Limit Enforcement Checks The study was made in order to gather basic information about the views of drivers on matters concerning speeding checks using driver interviews and speed measurements. The subjective risk of getting caught experienced by the drivers was of special interest. The relation between the actual speeds of the drivers and their views on speeding checks, and the views of the drivers on a method of speeding check that is rapidly spreading in Finland, i.e. automatic speed cameras were also studied.

The study was made by measuring the speeds of cars and vans, when there were no traffic jams, with a hidden speed radar.

After measuring their speed, the vehicles were pulled over and the drivers were asked to answer a questionnaire about speeding.

Over 60 per cent of the drivers answering the questionnaire supposed that the police enforced speed limits on the routes mostly used by these drivers at least once a month. A third of the drivers thought that the speeding checks were carried out at most a couple of times a year.

About 10 per cent of the drivers sup28

posed that traditional police speeding check had zero tolerance. 15–20 per cent of the drivers supposed that automatic speed cameras had zero tolerance. Most drivers, about 80 per cent, estimated the tolerance to be at most 10 km/h. On country roads about 15 per cent of the drivers thought that speeding check tolerance was higher than 10 km/h.

About 60–70 per cent of the drivers thought that the police should punish those exceeding the speed limit by less than 15 km/h with a fine. About 80–90 per cent of the drivers thought that police should punish those breaking the speed limit by less than 10 kmph with at least a warning.

Almost all drivers had driven on a road with automatic speed cameras. 86

per cent of the drivers thought that automatic speed cameras were acceptable while 11 per cent thought they were inappropriate. The ones driving frequently on roads with automatic speed cameras supposed that the speeding check tolerance was higher than the ones driving less frequently on them.

Examination of the actual speeds of the drivers interviewed, showed that the lower the speeds, the lower the supposed enforcement tolerance was. Of the drivers speeding by over 10 km/h, about 80 per cent hoped that the police would just issue a warning, and 25 per cent hoped the police would issue a fine for speeds even lower than the excess speed measured.

Titel: Drivers’ views on the frequency and tolerance of speed limit enforcement checks Authors: Leif Beilinson, Rita Rathmayer and Arja Wuolijoki Series: VTT Research Notes 2242 Language: Finnish with English abstract http://www.vtt.fi/inf/pdf/tiedotteet/2004/T2242.pdf

NORDIC ROAD & TRANSPORT RESEACH NO. 3 2004

Annotated reports from the Swedish National Road and Transport Research Institute, VTI

The proportion of senior citizens (aged 65+) will increase from about 15 per cent in the year 2000 to about 30 per cent in the year 2050. The share of older drivers in the driving population will grow even faster because of the increasing number of driving licence holders among the ageing population.

Generally speaking, safety measures targeted at older drivers are beneficial for all drivers. In the present report, measures are described that focus on the drivers, on the traffic environment, on vehicles and on ITS applications.

The aim of the present report is to provide a review of older drivers, with special emphasis on older drivers’ safety and mobility needs. The report focuses on the issues of older driver population heterogeneity, infrastructure developments, and on the even older drivers (aged 75+). An effort is also made to forecast some expected changes in the transportation system and in the population of older drivers.

Conclusions and recommendations: 1) Older drivers as a group drive just as safely as younger experienced drivers

PHOTO: THOR BALKHED/BILDAMEDIA

Safety Measures Targeted at Older Drivers Are Beneficial for All Drivers

2) Older drivers do not constitute an increased risk for their fellow road-users 3) Screening of drivers of a certain age is not an effective measure for increasing traffic safety 4) When older drivers are involved in an accident they run a higher risk of being seriously injured or killed compared to younger age groups. This is due to greater fragility related to their age 5) Compared to other modes of transportation, driving is also for old drivers 6) Traffic safety should be viewed from a public health perspective in order to balance the legitimate demands of ageing citizens concerning both mobility and safety

7) The mobility of the aging citizens who drive can be improved by supporting the continuation of driving especially for old women as well as by improving the design of cars and roads.

Title: Older drivers – a review Authors: Liisa Hakamies-Blomqvist, Anu Sirén and Ragnhild Davidse Series; VTI rapport 497A Language: English The report is also available as a pdf file on www.vti.se/ Publications.

The Effects of Speed and Side Acceleration Related to the Location of the Centre of Rotation for Banking of Sharp Curves choice of speed and side acceleration and secondly that these results were not influenced by training.

The results show firstly that the location of the centre of rotation for banking of sharp curves influenced the drivers’

NORDIC ROAD & TRANSPORT RESEACH NO. 3 2004

PHOTO: GABRIEL HELMERS/VTI

Sharp curves constitute a significant safety risk. The question is whether it is possible to design sharp curves in such a way that drivers take them with greater margins of safety. In this work it was studied whether the drivers’ choice of speed and side acceleration would change with the location of the centre of rotation for banking of sharp curves.

The influence of training was also studied.

The study was carried out in VTI’s driving simulator (Model I).

Title: The effects of speed and side acceleration related to the location of the centre of rotation for banking of sharp curves, and the influence of training – an experiment in a driving simulator.

Authors: Gabriel Helmers and Jan Törnros Series: VTI meddelande 967 Language: Swedish with English summary The report is also available as a pdf file on www.vti.se/ Publications.

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Annotated Annotated reports reports from from the Swedish National Road and Transport Research Institute, VTI

Tunnels for road and street traffic are becoming increasingly important for transport provision, primarily in large cities. Currently, there are high-volume tunnels in the primary road networks in Stockholm and Gothenburg. In addition, many new tunnels will soon be finalised or are planned both in Stockholm and Gothenburg.

Exhaust emissions in road tunnels are not allowed to exceed certain limits.

Road tunnels are equipped with ventilation systems to make sure that the air pollution limits are not exceeded, primarily concerning NO2 emissions. The ventilation systems are dimensioned using data on maximum expected emissions per unit of time.

VTI has been commissioned by the Swedish Road Administration (SRA) to develop a model for the calculation of exhaust emissions in tunnels, which in addition shall take into account oversaturated conditions. Currently, SRA has no satisfactory model for making such calculations on an hourly basis.

The objective of the development task has been to formulate a calculation model for travel speeds and emissions in motorway tunnels which can be used when tun-

PHOTO: CHRISTIAN LAGEREEK

Emission Model for Road Tunnels

nel ventilation systems are dimensioned.

For a complete structure, the model shall provide individual tunnel tube emission data for hourly traffic, split into homogenous – from the traffic engineering point of view– road links and ventilation segments.

This report describes the results of the development project for calculating emissions in tunnels. The completed model consists of two parts, one for the calculation of speed and corresponding hourly flow at any given demand level

and one for the calculation of emissions using hourly flows and speed as input data. There is a computer program for each part with user manuals.

Test runs with the model for some basic typical tunnel cases have been carried out to illustrate the results of the total model. The total emissions of NOx (kg/km) as a function of traffic flow have been calculated for different degrees of traffic load.

In addition, the model has been validated by comparisons of calculated NOx values from the model with NOx values measured in three different tunnels: the Gnistäng tunnel and the Tingstad tunnel in Gothenburg and the Southern Route tunnel in Stockholm.

Title: An emission model for road tunnels Authors: Arne Carlsson, Ulf Hammarström and Bo O. Karlsson Series: VTI meddelande 968 Language: Swedish with English summary The report is also available as a pdf file on www.vti.se/Publications.

Comparison of Car-Following Models

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similarities and differences between the models as well as models’ individual properties are clarified.

Two of the four models, the Fritzsche model and the model included in VISSIM, have a similar approach to carfollowing, whereas the other two models have fundamentally different approaches.

However, the resulting following behaviours of the models show similarities even though the car-following approaches are different.

PHOTO: JOHAN KNUTSSON

Traffic simulation is a tool often used in the study of traffic systems. A traffic simulation model consists of several submodels with each one handling one specific task in the simulation. These submodels include, among other things, carfollowing. This model controls the interactions with the vehicle in front in the same lane.

This paper compares and describes the car-following models used in the four traffic micro-simulation software packages AIMSUN, MITSIM, VISSIM, and the Fritzsche car-following model. A variant of the Fritzsche model is used in the software tool Paramics. Paramics exists in two versions. The differences between the car-following models used in these versions and the Fritzsche car-following model are, however, unknown. Both

Title: Comparison of car-following models Authors: Johan Janson Olstam and Andreas Tapani Series: VTI meddelande 960A Language: English The report is also available as a pdf file on www.vti.se/Publications.

NORDIC ROAD & TRANSPORT RESEACH NO. 3 2004

Annotated reports from the Swedish National Road and Transport Research Institute, VTI

Characteristics of Competitiveness in Public Transport Systems Based on Trams and on Buses Respectively buses show a weaker system image. High quality bus systems with e.g. a high degree of separate bus lanes, priority at traffic lights and real time passenger information, as well as articulated buses and trolleybuses, show an intermediate system image. The structuring effects of tram routes on building activities and other establishments are obvious. When a new tram system is established, private car traffic is often restricted in various ways. The extent of restrictions is not equally obvious when new bus systems are established. New tram systems are used not only as a means of transportation but also as a tool for refurbishing the city environment.

This includes establishing pedestrian areas, restrictions on car use and establishing parking and cycling facilities.

The so-called Rail Factor has been specially investigated, but has been difficult to prove just for public transport with trams. It has not been possible to identify any exact limits for passenger volumes carried best by buses or by trams; the values are really fluent. However, public transport makes use of street space much more efficiently than car traffic does.

Trams are more than twice as efficient as buses, considering the numbers of passengers carried. In the period 1986–1996 European cities basing their public transport on trams, showed a larger growth in the numbers of passengers carried than those cities which relied on buses.

on traffic in cities. It has been carried out as a literature study, combined with detailed studies of four specific cities, where the transport developments show different patterns: Jönköping and Stockholm in Sweden, Rouen in France and Essen in Germany. Generally, tram operations have a rather strong system image, whereas

PHOTO: GÖRAN BILLESON

PHOTO: THOR BALKHED/BILDAMEDIA

This report, “Characteristics of competitiveness for public transport systems based on trams and on buses respectively”, is a part of the research programme “Light Rail – Light Cost II”. It aims to identify factors which lead to successful public transport systems based on these means of transportation. The report focuses

NORDIC ROAD & TRANSPORT RESEACH NO. 3 2004

Title: Characteristics of competitiveness for public transport systems based on trams and on buses respectively.

Author: Thomas Johansson Series: VTI meddelande 948 Language: Swedish with English summary The report is also available as a pdf file on www.vti.se/ Publications.

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Questions concerning the content of the articles, or orders for the publications referred to, should be directed to the publishing institution, see addresses below.

REQUEST FOR BACK ISSUES, AND NOTIFICATION OF ADDRESS CHANGES. Readers outside the Nordic countries: see Swedish address.

Readers in the Nordic countries: see addresses below.

Web site: www.vti.se/nordic

Denmark Helen Hasz-Singh Danish Road Institute P.O. Box 235 DK-4000 Roskilde Phone: +45 46 30 70 00 Fax: +45 46 30 71 05 E-mail: hhz@vd.dk Web site: www.vd.dk

Norway Harald Aas Institute of Transport Economics (TØI) P.O. Box 6110 Etterstad N-0602 Oslo Phone: +47 22 57 38 00 Fax: +47 22 57 02 90 E-mail: harald.aas@toi.no Web site: www.toi.no

Finland Kari Mäkelä VTT Building and Transport P.O. Box 1800 FIN-02044 VTT Phone: +358 9 45 64 586 Fax: +358 9 46 48 50 E-mail: kari.s.makela@vtt.fi Web site: www.vtt.fi/rte/indexe.html

Norway Thorbjørn Chr. Risan Norwegian Public Roads Administration P.O. Box 8142 Dep N-0033 Oslo Phone: +47 73 95 46 48 Fax: +47 73 95 46 31 E-mail: thorbjorn.risan@vegvesen.no Web site: www.vegvesen.no

Iceland Hreinn Haraldsson Public Road Administration Borgartún 7 IS-105 Reykjavik Phone: +354 563 1400 Fax: +354 562 2332 E-mail: hrh@vegag.is Web site: www.vegagerdin.is

Sweden Tarja Magnusson Swedish National Road and Transport Research Institute (VTI) SE-581 95 Linköping Phone: +46 13 20 42 15 Fax: +46 13 14 14 36 E-mail: tarja.magnusson@vti.se Web site: www.vti.se