CTR Library Research Digest -- Aug 2010

Research Digest FORWARD ALL REQUESTS TO: The University of Texas at Austin Center for Transportation Research LIBRARY 1616 Guadalupe St. ‡ 6XLWH ‡ $XVWLQ ‡ 7H[DV ‡ Phones: (512) 232-3126 and (512) 232-3138 Email: ctrlib@austin.utexas.edu

In this Issue: Southwest Region University Transportation Center (SWUTC) Reports

Table of Contents Item 1. An Evaluation of Alternative Fuels Usage by Public Transit Agencies (SWUTC/06/167321-1) ....... 1 Item 2. Intelligent Transportation Systems Data Compression Using Wavelet Decomposition Technique (SWUTC/09/167651-1) ............................................................................................................................... 1 Item 3. Multimodal Network Models for Robust Transportation Systems (SWUTC/09/167867-1)............... 2 Item 4. Driver Eye-Scanning Behavior at Intersections at Night (SWUTC/09/169111-1)............................. 3 Item 5. Evolution of the Household Vehicle Fleet (SWUTC/09/169202-1) .................................................. 3 Item 6. A Methodology for Incorporating Fuel Price Impacts into Short-term Transit Ridership Forecasts (SWUTC/09/169203-1) ............................................................................................................................... 4 Item 7. Trip Internalization and Mixed-Use Development (SWUTC/09/169207-1)...................................... 4 Item 8. Laboratory Investigation of a Novel Method to Accelerate Healing in Asphalt Mixtures Using Thermal Treatment (SWUTC/09/476660-00005-1) ..................................................................................... 5 Item 9. Improving the Sustainability of Asphalt Pavements through Developing a Predictive Model with Fundamental Material Properties (SWUTC /09/476660-00007-1) ................................................................ 5 Item 10. Bush School Capstone Course Support (SWUTC/09/476660-00010-1) ......................................... 6 Item 11. Developing and Applying Mobility Performance Measures for Freight Transportation in Urban Areas (SWUTC/09/476660/00014-1) .......................................................................................................... 6 Item 12. Sustainable Intersection Control to Accommodate Urban Freight Mobility (SWUTC/09/47666000015-1)..................................................................................................................................................... 7 Item 13. Pilot Information System for Cross-Border HAZMAT Transportation (SWUTC/09/476660-000161) ............................................................................................................................................................... 7 Item 14. Dynamic Traffic Assignment-Based Trailblazing Guide Signing for Major Traffic Generator (SWUTC/09/476660-00046-1) .................................................................................................................... 8 Item 15. Vehicle and Driver Scheduling for Public Transit (SWUTC/09/476660-00063-1).......................... 8 Item 16. A Statistical Analysis of the Relationship between Land Values and Freestanding Bus Facilities (SWUTC/10/167372-1) ............................................................................................................................... 9 Item 17. Addressing Safety through Evaluation and Optimization of Permeable Friction Course Mixtures (SWUTC/10/476660-00013-1) .................................................................................................................... 9 Item 18. Southwest Region University Transportation Center Annual Report 2009 (SWUTC Annual Report 2009) ....................................................................................................................................................... 10 Research and Technology Implementation Office, August 2010

Research Digest Item 1 An Evaluation of Alternative Fuels Usage by Public Transit Agencies SOUTHWEST REGION UNIVERSITY TRANSPORTATION CENTER (SWUTC) SWUTC/06/167321-1 • 2009 The oil crisis of the 1970s forced Americans to reconsider using fossil fuels as a primary energy source. In the public transit arena, private transit companies found themselves unable to compete in the urban environment as rapidly rising oil prices negatively affected the economy and personal mobility. In response to the growing energy crises, the American government initiated policies designed to reduce the dependence on foreign oil.

These new policies were implemented to reduce pollution, maintain fuel efficiency, and develop alternative fuels for use by private auto owners, governmental entities, and transit companies. This study offers a historical examination of the key legislation passed during the period of the 1970s - 2000s, provides a discussion of the types of alternative fuels developed and examines how transit agencies applied those technologies to try to meet the spirit of the legislation.

Full-text PDF of this report is available for free download from: http://swutc.tamu.edu/publications/technicalreports/167321-1.pdf

Item 2 Intelligent Transportation Systems Data Compression Using Wavelet Decomposition Technique SOUTHWEST REGION UNIVERSITY TRANSPORTATION CENTER (SWUTC) SWUTC/09/167651-1 • 2009 Intelligent Transportation Systems (ITS) generates massive amounts of traffic data, which poses challenges for data storage, transmission and retrieval. Data compression and reconstruction technique plays an important role in ITS data procession. Traditional compression methods have been utilized in Transportation Management Centers (TMCs), but the data redundancy and compression efficiency problems remain. In this report, the wavelet incorporated ITS data compression method is initiated. The proposed method not only makes use of the conventional compression techniques but, in addition, incorporates the one-dimensional discrete wavelet compression approach. Since the desired wavelet compression is a lossy algorithm, the balancing between the compression ratio and the signal distortion is exceedingly important. During the compression process, the determination of the threshold is the key issue that affects both the compression ratio and the signal distortion.

An algorithm is proposed that can properly select the threshold by balancing the two contradicted aspects. Three performance indexes are constructed and the relationships between the three indices and the threshold are identified in the algorithm. A MATLAB program with the name Wavelet Compression for ITS Data (WCID) has been developed to facilitate the compression tests. A case study on TransGuide ITS data was put into play and a final compression ratio of less than one percent on the trade-off threshold value shows that the proposed approach is practical. Finally, the threshold selection algorithm can be further tuned up utilizing Autoregressive model so that the quality of reconstructed data can be improved with a minor overhead of saving only a few parameters.

Full-text PDF of this report is available for free download from: http://swutc.tamu.edu/publications/technicalreports/167651-1.pdf

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Research Digest Item 3 Multimodal Network Models for Robust Transportation Systems SOUTHWEST REGION UNIVERSITY TRANSPORTATION CENTER (SWUTC) SWUTC/09/167867-1 • 2009 Since transportation infrastructure projects have a lifetime of many decades, project developers must consider not only the current demand for the project but also the future demand. Future demand is of course uncertain and should be treated as such during project design. Previous research for Southwest Region University Transportation Center (Report 167556) explored the impact of uncertainty on roadway improvements and found neglecting uncertainty to lead to suboptimal network design decisions. This research is extended in the current work by considering not only motor vehicle traffic, but other modes as well.

The first half of this report examines the problem of network flexibility in the face of uncertainty when constructing a potentially revenue-generating toll road project. Demand uncertainty and network design are considered by way of a bi-level stochastic recourse model. The results from a test network, for which a closed form solution is possible, indicate that the value of network flexibility directly depends on initial network conditions, variance in future travel demand, and toll pricing decisions.

The second half of this report integrates Environmental Justice into the transit frequency-setting problem while considering uncertainty in travel demand from protected populations. The overarching purpose is to improve access via transit to basic amenities to: (1) reduce the disproportionate burden transit dependent populations' experience; and (2) increase the financial security of low-income households by giving them a feasible option to reduce their dependence on autos. The example application illustrates the formulation successfully increases access to employment opportunities for residents in areas with the high percentages of low-income persons, as well as demonstrates the importance of considering uncertainty in the locations of low-income populations and employment.

Full-text PDF of this report is available for free download from: http://swutc.tamu.edu/publications/technicalreports/167867-1.pdf

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Research Digest Item 4 Driver Eye-Scanning Behavior at Intersections at Night SOUTHWEST REGION UNIVERSITY TRANSPORTATION CENTER (SWUTC) SWUTC/09/169111-1 • 2009 This research project analyzed drivers’ eye scanning behavior at night when approaching signalized and unsignalized intersections using the data from a head-mounted eye-tracking system during open road driving on a prescribed route. During the 1000-ft approaching the intersections, drivers shifted their glance more frequently when approaching the signalized intersections than they did at unsignalized intersections. Among different turning movements, left turns overall seemed to elicit different eye movement patterns than the right-turn or through-movements. When approaching intersections where they would turn left, the drivers glanced most often straight ahead, while glances to the right side decreased in frequency and glances to the left increased in frequency compared to the right-turn and through-movement intersections. This study used a binary logistic regression model to analyze the changes of probabilities of glances to each of four areas of the scene as a function of distance to the intersections. At some intersections, the probabilities of glances at particular areas significantly changed with the distance to the intersection. The report also discusses methodological issues with on-road studies, the coding of eye-tracker data, and problems with eye-tracking equipment.

Full-text PDF of this report is available for free download from: http://swutc.tamu.edu/publications/technicalreports/169111-1.pdf

Item 5 Evolution of the Household Vehicle Fleet : Anticipating Fleet Composition, Plug-In Hybrid Electric Vehicle (PHEV) Adoption and Greenhouse Gas (GHG) Emissions in Austin, Texas SOUTHWEST REGION UNIVERSITY TRANSPORTATION CENTER (SWUTC) SWUTC/09/169202-1 • 2009 Automobile ownership plays an important role in determining vehicle use, emissions, fuel consumption, congestion and traffic safety. This work provides new data on ownership decisions and owner preferences under various scenarios, coupled with calibrated models to microsimulate Austin's household-fleet evolution. Results suggest that most Austinites (63%, population-corrected share) support a feebate policy to favor more fuel efficient vehicles. Top purchase criteria are vehicle purchase price, type/class, and fuel economy (with 30%, 21% and 19% of respondents placing these in their top three). Most (56%) respondents also indicated that they would seriously consider purchasing a Plug-In Hybrid Electric Vehicle (PHEV) if it were to cost $6,000 more than its conventional, gasoline-powered counterpart. And many respond strongly to signals on the external (health and climate) costs of a vehicle's emissions, more strongly than they respond to information on fuel cost savings. 25year simulations suggest that 19% of Austin's vehicle fleet could be comprised of Hybrid Electric Vehicles (HEVs) and PHEVs under adoption of a feebate policy (along with PHEV availability in Year 1 of the simulation, and current gas prices throughout). In comparison to the base year (2009) total VMT, year 2034 vehicle miles traveled (VMT) levels are predicted to increase 154% by year 2034 in the TREND scenario. Total CO2 emissions fall by 22% in the PRICING scenario relative to the TREND scenario.

Full-text PDF of this report is available for free download from: http://swutc.tamu.edu/publications/technicalreports/169202-1.pdf _____________________________________________________________________________________________

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Research Digest Item 6 A Methodology for Incorporating Fuel Price Impacts into Short-term Transit Ridership Forecasts SOUTHWEST REGION UNIVERSITY TRANSPORTATION CENTER (SWUTC) SWUTC/09/169203-1 • 2009 Anticipating changes to public transportation ridership demand is important to planning for and meeting service goals and maintaining system viability. These changes may occur in the short- or long-term; extensive academic work has focused on bettering long-term forecasting procedures while improvements to short-term forecasting techniques have not received significant academic attention. This dissertation combines traditional forecasting approaches with multivariate regression to develop a transferable short-term public transportation ridership forecasting model that incorporates fuel price as a prediction parameter. The research herein addresses 254 US transit systems from bus, light rail, heavy rail, and commuter rail modes, and uses complementary methods to account for seasonal and non-seasonal ridership fluctuations. Models were built and calibrated using monthly data from 2002 to 2007 and validated using a six-month dataset from early 2008. Using variable transformations, classical data decomposition techniques, multivariate regression, and a variety of forecasting model validation measures, this work establishes a benchmark for future research into transferable transit ridership forecasting model improvements that may aid public transportation system planners in an era when, due to fuel price concerns, global warming and green initiatives, and other impetuses, transit use is seeing a resurgence in popularity.

Full-text PDF of this report is available for free download from: http://swutc.tamu.edu/publications/technicalreports/169203-1.pdf

Item 7 Trip Internalization and Mixed-Use Development : A Case Study of Austin, Texas SOUTHWEST REGION UNIVERSITY TRANSPORTATION CENTER (SWUTC) SWUTC/09/169207-1 • 2009 The Capital Area Metropolitan Planning Organization (CAMPO) in the Austin, TX region is incorporating a new regional growth concept, the Activity Centers for its Long-Range Transportation Plan. The planned Activity Centers would present such features as mixed uses, medium to high densities, and pedestrian friendly environmental design, which are expected to influence travel. This study reports the needed local empirical evidence of trip making behavior in association with the Activity Centers' attributes. From telephone interviews of local planners and work sessions with experts, the study identifies 42 mixed-use districts (MXDs) in the Austin area. In GIS, urban form indicators are derived for the MXDs and trip records from the 2005 Austin Activity Travel Survey are geocoded. The following analyses are then carried out for the MXD related travel: trip length distribution, trip generation rates and internal rate of capture, person miles of travel, vehicle ownership, departure time, and travel mode choice. With the empirical results, CAMPO models can be modified or refined to capture the potential effects of the Activity Centers growth strategy on regional travel.

Full-text PDF of this report is available for free download from: http://swutc.tamu.edu/publications/technicalreports/169207-1.pdf

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Research Digest Item 8 Laboratory Investigation of a Novel Method to Accelerate Healing in Asphalt Mixtures Using Thermal Treatment SOUTHWEST REGION UNIVERSITY TRANSPORTATION CENTER (SWUTC) SWUTC/09/476660-00005-1 • 2009 Asphalt binders have an inherent ability to reverse damage in the form of micro-cracks that is caused due to the repeated action of external loads. This reversal occurs during rest periods between load cycles. The phenomenon of crack reversal is referred to as autogenous or self-healing. The main objective of this project was to apply established principles of healing to investigate a novel technique to accelerate reversal of accumulated microcrack in asphalt mixtures. This technique was developed and evaluated using a laboratory scale set up. Laboratory tests were used to evaluate the impact of thermal treatment on the fatigue cracking life of asphalt mixtures.

Results from this study indicate that for two out of the three different types of asphalt mixtures, intermittent application of the thermal treatment resulted in approximately 50% increase in the fatigue cracking life of the mixture.

Full-text PDF of this report is available for free download from: http://swutc.tamu.edu/publications/technicalreports/476660-00005-1.pdf

Item 9 Improving the Sustainability of Asphalt Pavements through Developing a Predictive Model with Fundamental Material Properties SOUTHWEST REGION UNIVERSITY TRANSPORTATION CENTER (SWUTC) SWUTC/09/476660-00007-1 • 2009 This study presents the numerical implementation and validation of general constitutive relationships for describing the nonlinear behavior of asphalt concrete mixes. These constitutive relationships incorporate nonlinear viscoelasticity and viscoplasticity to predict the recoverable and irrecoverable responses, respectively.

The nonlinear viscoelastic deformation is modeled using Schapery’s model; while the irrecoverable component is represented using Perzyna’s viscoplasticity theory with an extended Drucker-Prager yield surface and plastic potential that is modified to capture the distinction between the compressive and extension behavior of asphalt mixes. The nonlinear viscoelastic and viscoplastic model is represented in a numerical formulation and implemented in a finite element (FE) code using a recursive-iterative algorithm for nonlinear viscoelasticity and the radial return algorithm for viscoplasticity. Then, the model is used to analyze the nonlinear viscoelastic and viscoplastic behavior of asphalt mixtures subjected to single creep recovery tests at different stress levels and temperatures. This experimental analysis includes the separation of the viscoelastic and viscoplastic strain components. Based on this separation, a systematic procedure is presented for the identification of the material parameters associated with the nonlinear viscoelastic and viscoplastic constitutive equations. Finally, the model is applied and verified against a set of creep-recovery tests on hot mix asphalt at different stress levels and temperatures.

Full-text PDF of this report is available for free download from: http://swutc.tamu.edu/publications/technicalreports/476660-00007-1.pdf

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Research Digest Item 10 Bush School Capstone Course Support : The Regional Impact of Climate Change on Transportation Infrastructure and Decision Making SOUTHWEST REGION UNIVERSITY TRANSPORTATION CENTER (SWUTC) SWUTC/09/476660-00010-1 • 2009 The Master of Public Service and Administration program at Texas A&M’s Bush School of Government and Public Service requires that all second year graduate students participate in a two semester Capstone course.

These courses represent the practical culmination of the degree program and are based on a real world research experience. For the 2008-09 school year, one of these Capstone efforts focused on the significant impact climate change will have on infrastructure and decision making in the Houston-Galveston area. Attention has recently shifted from the impact of transportation on climate to a focus on adaptation to potential climate stressors of sea level rise, increased frequency and magnitude of storms and severe weather events, and changes in precipitation and temperature. The Houston-Galveston Area Council (H-GAC) recognized this situation and agreed to support a Capstone class and project focusing on these issues. The Capstone report is included in this SWUTC report as Appendix A. Full-text PDF of this report is available for free download from: http://swutc.tamu.edu/publications/technicalreports/476660-00010-1.pdf

Item 11 Developing and Applying Mobility Performance Measures for Freight Transportation in Urban Areas SOUTHWEST REGION UNIVERSITY TRANSPORTATION CENTER (SWUTC) SWUTC/09/476660-00014-1 • 2009 This report summarizes the activities performed in a one-year study with the objective to develop an understanding of the interrelationships of urban goods movement and congestion and identify performance measures that will help evaluate the impact of goods movement in the urban area. Through a survey instrument and state-of-the-practice review, this research project investigated the impacts and interactions of commodity movements within an urban area, given traffic congestion.

Researchers generally found that traditional mobility monitoring performance measures (e.g. delay, travel time index) can be adopted for freight-related mobility performance measurement. From the surveys conducted, and the state-of-the-practice review, researchers also found that (1) recurring congestion and most typical incident congestion is a problem that carriers/shippers can plan for and, in most cases, they can deal with congestion as it comes along; and (2) carriers/shippers tend to estimate a time cushion (buffer) into their schedules to meet their delivery times. There are times when urban congestion levels can impact freight operations (e.g. just-in-time (JIT) deliveries for manufacturing, less-than-truckload (LTL) trips by truck). Researchers also documented the interrelationship of how decisions by either the public sector or the trucking companies can influence one another.

Full-text PDF of this report is available for free download from: http://swutc.tamu.edu/publications/technicalreports/167321-1.pdf

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Research Digest Item 12 Sustainable Intersection Control to Accommodate Urban Freight Mobility SOUTHWEST REGION UNIVERSITY TRANSPORTATION CENTER (SWUTC) SWUTC/09/476660-00015-1 • 2009 In this research, we studied green extension of a two-phased vehicle-actuated signal at an isolated intersection between two one-way streets. The green phase is extended by a preset time interval, referred to as critical gap, from the time of a vehicle arrival. The green phase switches if there is no arrival during the critical gap. We developed a model following a Poisson process that studied the intersection performance of traffic. We extended the model to cover the case of general traffic. Additionally, we derived system performance measures. Our findings show that our model is fairly flexible in accommodating freight traffic, and our model in the general case is asymptotically accurate under heavy traffic. Numerical tests show that the presence of critical gaps increases vehicle delay in most cases. This finding is enlightening regarding current practices.

Full-text PDF of this report is available for free download from: http://swutc.tamu.edu/publications/technicalreports/476660-00015-1.pdf

Item 13 Pilot Information System for Cross-Border HAZMAT Transportation SOUTHWEST REGION UNIVERSITY TRANSPORTATION CENTER (SWUTC) SWUTC/09/476660-00016-1 • 2009 Under NAFTA requirements, all hazardous materials that are shipped into Mexico or generated during the manufacturing process must be shipped back to its point of origin, typically the United States. Thus, the delivery and return of hazardous materials have created a HAZMAT transportation corridor. At present, there is no automated, real-time method to track hazardous materials shipments crossing the U.S.-Mexico border. As a result, border agencies (specially the first responders) do not have advanced information about the hazardous materials being transported through border crossings and other locations within their communities. This lack of information hinders first responder’s ability to respond to hazardous materials incidences.

The objective of the study was to propose a prototype of an information system by which hazardous materials movement will be relayed and/or shared with local and regional agencies (mainly the first responders) which will assist these agencies to respond to major hazardous materials incidents more efficiently. This prototype information system was designed for first responders as a model for what could be developed for the wide range of stakeholders from all U.S. and Mexican border states. A large part of the initial research was spent in identifying the agencies that played minor and major roles in transportation of hazardous materials across the border. The researchers found that a large number of agencies played various roles in what turned out to be extremely complicated process of hazardous materials transportation and incident response. Finally, based on stakeholder needs, the research proposed logical and physical architecture of a prototype system to monitor movement of hazardous materials in the border area and to provide advanced warning of hazardous materials related incidents to the first responders.

Full-text PDF of this report is available for free download from: http://swutc.tamu.edu/publications/technicalreports/476660-00016-1.pdf

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Research Digest Item 14 Dynamic Traffic Assignment Based Trailblazing Guide Signing for Major Traffic Generator SOUTHWEST REGION UNIVERSITY TRANSPORTATION CENTER (SWUTC) SWUTC/09/476660-00046-1 • 2009 The placement of guide signs and the display of dynamic message signs greatly affect drivers' understanding of the network and therefore their route choices. Most existing dynamic traffic assignment models assume that drivers heading to a Major Traffic Generator (MTG) have sufficient knowledge of roadway networks. In this report, the concept of recognition level is defined to categorize drivers based on their unfamiliarity of the network and of the alternative routes between origins and destinations. Each catalog is assigned a specific utility function that is dependent on travel time, length of route and recognition parameters. Drivers' route choice behavior is determined by these specific utility functions. A sample network is first employed to test the feasibility of the proposed model, and the result complies with the specified travel patterns. After that, a real network near Downtown Houston is used to further test the proposed model. An experiment is conducted based on the information collected from an on-site survey and the on-line real-time traffic map from Houston TranStar.

In order to validate the necessity of the proposed model, a control experiment is carried out with all parameters being set in the same way as the designed experiment except that drivers are assumed to be fully familiar with the network layout and alternative routes. Test results show that the proposed model can fit the real case very well.

The developed algorithm and the assessment procedure results are not only awfully imperative in trailblazing guide signing for MTGs, but also indispensable in both the modern Route Guidance System (RGS) and the Advanced Traveler Information System (ATIS), which are important components of the Intelligent Transportation System (ITS).

Full-text PDF of this report is available for free download from: http://swutc.tamu.edu/publications/technicalreports/476660-00046-1.pdf

Item 15 Vehicle and Driver Scheduling for Public Transit SOUTHWEST REGION UNIVERSITY TRANSPORTATION CENTER (SWUTC) SWUTC/09/476660-00063-1 • 2009 The problem of driver scheduling involves the construction of a legal set of shifts, including allowance of overtime, which cover the blocks in a particular vehicle schedule. A shift is the work scheduled to be performed by a driver in one day, while a block is a sequence of trips made by a single bus. Blocks can be divided between different drivers if they begin or end at relief points, providing the opportunity for change. The goal is to make the schedule as efficient as possible, therefore minimizing the amount of changes that need to be made.

The research contained herein describes work undertaken by the research team, including literature review and a survey of existing methodologies. Preliminary programming code was created to act as a benchmark for future endeavors in this area and elaboration of the complicating factors led the team to conclude that in order to fully complete a comprehensive working scheduling technique, substantially greater resources would be needed.

Full-text PDF of this report is available for free download from: http://swutc.tamu.edu/publications/technicalreports/476660-00063-1.pdf

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Research Digest Item 16 A Statistical Analysis of the Relationship Between Land Values and Freestanding Bus Facilities SOUTHWEST REGION UNIVERSITY TRANSPORTATION CENTER (SWUTC) SWUTC/10/167372-1 • 2010 Public transit professionals continue to seek methods that offer greater service opportunities, while not materially increasing the costs of service provision. One strategy is to construct bus transit centers which operate much like the airline hub and spoke concept. More frequent destinations can be made available with shorter patron wait times and minimal to no increase in the number of bus hours. Patrons tend to appreciate the convenience of a transfer occurring in a lighted facility, in addition to the increased level of bus service. In many cases, there is an anticipation of higher density residential near these areas. A number of the bus based centers may be close to single family neighborhoods. Residents might express concerns about the value of their property given the presence of a bus transit center near their home. Besides the bus transit centers that serve traditional local or express routes, a number of cities are planning bus rapid transit lines with stations that might lead nearby communities to ask similar questions about property values. This study assesses the effect of bus transit centers in Houston, Texas, on nearby single family residential property values.

Full-text PDF of this report is available for free download from: http://swutc.tamu.edu/publications/technicalreports/167372-1.pdf

Item 17 Addressing Safety Through Evaluation and Optimization of Permeable Friction Course Mixtures SOUTHWEST REGION UNIVERSITY TRANSPORTATION CENTER (SWUTC) SWUTC/10/476660-00013-1 • 2010 Permeable friction course (PFC) mixtures are a special type of hot mix asphalt characterized by a high total air voids content to guarantee proper functionality and stone-on-stone contact of the coarse aggregate fraction to ensure adequate mixture stability. Thus, PFC mixtures constructed in a thin layer at the surface of a pavement structure produce several benefits in terms of economy, safety, and the environment. This project focused on the analysis of functionality (i.e. drainability), stone-on-stone contact, and mixture internal structure to propose improvements in these three aspects for PFC mix design and evaluation. The analysis was based on both a macroscopic assessment of mixture properties and a study of internal structure using X-ray Computed Tomography (X-ray CT) and image analysis techniques.

Full-text PDF of this report is available for free download from: http://swutc.tamu.edu/publications/technicalreports/476660-00013-1.pdf

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Research Digest Item 18 Southwest Region University Transportation Center Annual Report 2009 SOUTHWEST REGION UNIVERSITY TRANSPORTATION CENTER (SWUTC) SWUTC Annual Report 2009 • 2009 "Inside this Annual Report there are highlight pieces about some cutting edge topics being pursued in our research, education, and technology transfer programs. The topics range from high-speed rail investment in Texas to new freight patterns that will result from expanded capacity in the Panama Canal. The strategic imperatives of climate change impacts must become understood and then integrated into transportation policy and investments.

New technologies in construction materials are needed to extend the service lives of newly built infrastructure.

Expanded methodologies to utilize concepts such as mega-regions must be developed to support future transportation planning and policy. Some metrics defining “green transportation” must be developed and operationalized. And last in this list, but maybe first in difficulty, the economic resources and incentives needed for transformative transportation initiatives must be identified and harnessed into viable, sustainable constituencies.

"The academic programs within our consortium are also spotlighted herein to reflect SWUTC capacities to find and educate the best students available for conceptualizing, building, and operating the future transportation enterprises of this century. In the three universities, our students must be challenged to transcend traditional academic disciplines and create new linkages in tying transportation concepts into the socio-political framework of the culture." --Director's Statement, p.5 Full-text PDF of this report is available for free download from: http://swutc.tamu.edu/publications/annualreports/2009AnnualReport.pdf

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