Traffic Calming

TRAFFIC CALMING MEASURES USING URBAN DESIGN ELEMENTS

Introduction to Transportation planning Abhijeet Shrivastava MSAUD | GSAPP

ROAD TRAFFIC ACCIDENTS : A global concern.

The global status report released by WHO this year, confirms that road traffic injuries are still a big global health and development problem.

1.2 million Die in road accidents every year A further 50

million are injured.

Most of the countries lack a defined and systematic study process to facilitate traffic calming process

What is traffic calming?

Traffic calming is a technique to design streets using physical measures to control the dominance and speed of motor vehicles. It is a way of redesigning streets in order to return the streets to the neighborhood.

The goal of traffic calming is to make our streets safer and more comfortable for all users and residents.

Objective of traffic calming: The principal objective of traffic calming is to reduce the speed and volume of motor vehicles.

• • • • •

Protecting neighborhood areas from the unwanted heavy traffic.

Making the street friendly for pedestrians and Cyclists

Urban planning

Urban design

Reducing crash occurrence and severity. slowdown the traffic in high density areas.

Engineering measures

Reducing the environmental pollution caused by motor vehicles.

Traffic calming

Traffic calming measures Nonphysical measures

• • •

Psycho perception measure such as restriping to visually narrow lanes, without physical changes.

Regulatory measures such as stop signs and turn restrictions may slow or divert traffic in certain cases, but they require enforcement.

Signal timing on collectors and arterials to maintain for progression of green light on given street.

All the non-physical measure help in managing the traffic but the impact is less effective in traffic calming. Also the percentage of fatalities has not decreased. Therefor much focus should be given to physical measures.

Physical measures

• • •

Vertical deflections (most effective, but not used on main street) Horizontal deflections Combined measures (Physical + vertical + urban)

Vertical deflections Speed hump is the only speed control measure for which ‘Institute of Transportation Planning’ has made the guidelines.

The plateaus can be used for pedestrians and can be of longer width. Also use of different materials with contrasting color will improve its effectiveness.

Horizontal deflections Are less effective but helps in controlling the traffic movements. Fundamentally all horizontal shifts may be classified as chicanes.

Combined measures Using urban fabric as a tool to amplify the impact to existing calming measure.

Application of measures in combinations like Narrowing the carriageway with multiple speed tables.

Impacts of traffic calming measures • •

• •

Speed reduction Accident reduction (Slower vehicle speeds not only reduce the occurrence of accidents, but also have a significant effect on their severity.)

Environmental impact (noise reduction, air quality) Quality of street life (social life) Expected speed reduction effect of various traffic calming measures

Upper limit of max. speed (kph) Upper limit of 85 percentile speed (kph) Range of average speed (kph)

padestrian fatalities by speed of vehicle

Before

After

Before

After

Before

After

Vertical shifts in the carriageway

100

40

75

30

45-65

18-25

Lateral shifts in the carriageway

100

65

75

45

45-65

22-35

Road narrowing to a single lane

100

65

75

45

45-65

22-35

Roundabout

100

65

75

45

45-65

22-35

Road narrowing to a reduced width

100

95

75

70

45-65

40-55

Central islands

100

95

75

70

45-65

40-55

100% 80%

60% 40% 20% 0% 20 mph

30mph

40mph

Traffic calming schemes in Denmark has indicated that there has been a reduction of 43% in casualties compared with untreated areas.

NYC traffic condition and proposed applications :

Proposed use of traffic calming measures applied to some of the most dangerous intersections of New York City.

Most common reason comes to be

attention lost and close following of vehicles. drivers

1. 125th street and Lexington Ave, New York 2. w 96th street & broadway, new York

50%

Almost of those who die in traffic accidents are cyclists, pedestrians and motorcyclists.

125th street and Lexington Ave, New York-

Identified Problem-

• • • •

The buses head from all four directions. super hectic subway station. huge supermarket on one corner.

The traffic here is bumper-to-bumper .

Solution:

• • •

Raised crossway.

Increase in width of side walk Textured pavements for visual environment

w 96th street & broadway, new york-

Identified Problem:

• • •

People walk in hurry to catch the subway.

Screaming cars towards the West Side Highway. crosstown buses makes this a wild intersection.

Solution:

• • •

Curb extension to improve pedestrian visibility .

Raised sidewalks.

Focal point to the spot and gateway experience.

CONCLUSION :

• • • • • •

Traffic calming is no longer a special case but its application has to be done appropriately.

Improper design led to the negative effect.

The most effective traffic calming measures for reducing vehicle speed is vertical shifts but its application is limited.

New measures have to be designed for the main streets using the technique of combination and urban design.

Though it has minimal impact on traffic, they provide enormous benefits for pedestrians, bicyclists, residents, and streetscapes.

In NYC, street Intersections which have subway station are much crowded. Thus Applying traffic calming measures to make it more pedestrian friendly and to incorporate all the user is important.

Thank you.

Abhijeet Shrivastava.

MSAUD | GSAPP Columbia university. NY