“Traffic calming. The combination of street designs and traffic rules that deliberately reduces vehicle speeds by designing and building interventions (e.g. speed humps, raised crossings, chicanes) to improve safety for all road users, especially pedestrians and cyclists.” World Resources Institute’s “Cities Safer by Design” document
“The Institute of Transportation Engineers defines traffic calming as the combination of measures that reduce the negative effects of motor vehicle use, alter driver behavior, and improve conditions for non-motorized street users. Traffic calming consists of physical design and other measures put in place on existing roads to reduce vehicle speeds and improve safety for pedestrians and cyclists. For example, vertical deflections (speed humps, speed tables, and raised intersections), horizontal shifts, and roadway narrowing are intended to reduce speed and enhance the street environment for non-motorists. Closures that obstruct traffic movements in one or more directions, such as median barriers, are intended to reduce cut-through traffic. Traffic calming measures can be implemented at an intersection, street, neighborhood, or area-wide level.” U.S. Department of Transport website
Those are two definitions of “traffic calming” used internationally with a focus on improving safety.
Some “traffic calming” features are also known to:
- Decrease vehicle traffic volumes
- Increase noise & air pollution
- Obstruct and slow emergency vehicles
- Damage vehicles and cause passenger discomfort
- Cause drainage issues
- Reduce on-street parking
- Cause “great discomfort” to the disabled and elderly
The above list was constructed from these sources:
World Resources Institute’s “Cities Safer by Design” document
Road and street features which are installed as “traffic calming” can include:
- Curb extensions
- Chokers and neckdowns
- Planters and informal street furniture
- Chicanes and build-outs
- Speed cushions
- Speed humps, judder bars, and speed bumps
- Speed tables
- Traffic circles, roundels, mini-roundabouts, and larger roundabouts
- Raised pedestrian crossings and pedestrian platforms
- Raised intersections
- Rumble devices and rumble strips
- Speed control medians
- Diagonal diverters
- Coloured surfaces and unusual road markings
- Different road surface textures
- Bike lanes
- Median islands
- Street closures
- In-lane bus stops
- Road diets “…a reduction in the width or number of vehicular travel lanes, reducing the number of vehicular travel lanes”
The above list was constructed from these sources:
(Note: Some features and obstacles are installed primarily for other reasons. However, they have been considered “traffic calming” by some authorities and other institutions of influence)
https://www.nzta.govt.nz/resources/research/reports/300/
World Resources Institute’s “Cities Safer by Design” document
https://www.nzta.govt.nz/assets/resources/speed-management-guide-road-to-zero-edition/speed-management-guide-road-to-zero-edition.pdf https://www.wri.org/research/cities-safer-design
https://www.transportation.gov/mission/health/Traffic-Calming-to-Slow-Vehicle-Speeds
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