Speed management lowers the likelihood of severe or fatal traffic injuries by reducing the frequency and severity of crashes. For pedestrians, speed management creates safe conditions for crossing, walking along the corridor, or sharing space with cycle or motor vehicle traffic. For cyclists, lower speed reduces the number of overtaking events, improves visibility and reaction time, and greatly reduces the severity of crashes that do occur.
Low and consistent traffic speed decreases noise and air pollution that result from acceleration and deceleration, while reducing stress for vulnerable road users.
Highway design is very limited, but as speed is lowered, the design palette expands. Speed management strategies include cost-effective, readily implemented techniques for streets of every size, traffic volume level, context, and human activity level.
Geometric Traffic Calming Strategies
Reduce speeding by introducing vertical elements such as speed bumps or raised pedestrian crossings, and horizontal elements like curb extensions, pedestrian refuge islands, or lane narrowing, into the streetscape. Comprehensive design techniques use visual and other sensory inputs to signal to drivers that they are entering an interactive, multimodal space, rather than a traffic-only space.
Combining multiple speed reduction treatments, slow zones, also known as limited-speed zones or home zones, can be implemented in areas with lower speed limits than the rest of the city, such as around schools or residential areas. These should be identified with self-enforcing gateway treatments and signs to alert drivers to the reduced speed limit. See: Designing for Pedestrians.
Roadway and Lane Narrowing
Narrowing lanes and reducing the total amount of space available to vehicles reduces speeding. On one-way streets, excess road width can be repurposed for pedestrian, cycle, and transit facilities. In places with lower traffic volumes, conversion to two-way streets can lower speeds and improve driver attention by requiring negotiation with oncoming traffic.
When set to cycle- and transitfriendly speeds of 20–25 km/h, signal progressions can remove much of the incentive to speed. This tool can be applied inexpensively and effectively on almost any signalized street regardless of size, and is especially easy to implement on one-way streets.