Traffic calming is the use of physical solutions to reduce traffic speeds and/or cut-through traffic with the goal of making streets safer and more accessible for motorists, bicyclists, and pedestrians. It has been proven as an effective way to reduce speeding on residential streets, avoid traffic crashes, and prevent needless fatalities. By implementing proper traffic management devices, we can increase the safety of pedestrians and cyclists as well as decrease vehicular collisions in those areas.
One of the historically reliable methods for traffic calming is vertical deflection, which adds a height variation to the road, causing motor vehicles to slow when approaching. Horizontal shifts and roadway narrowing are another way to implement calming measures. As with vertical deflection, traffic volume itself is relatively unaffected. These techniques will reduce vehicle speed and enhance streetscapes with minimal impact on traffic volume.
Traffic engineers, public works officials, and urban planners have many strategies for traffic calming including speed humps or tables, emergency-friendly speed cushions, lane narrowing, traffic circles, and improved bicycle access with designated bike lanes. These solutions are used to create more complete streets that offer safe access to all users.
Improving the streetscape will lead to a more walkable and bikeable area and allow for healthier lifestyles in the surrounding community.
Traffic calming has been shown to:
Improve speed limit compliance
Decrease injury severity when crashes occur
Lower fatality rates
Encourage varied transportation modes
Improve street aesthetics
Increase property value
While solutions can be instituted at the street, neighborhood, or city-wide level, traffic calming is most effective when it is part of a proactive program to improve street safety based on highest need. This is often ascertained with a points program to determine where risk is highest.
Does it work?
Does traffic calming really slow cars down? Study after study has reached the same conclusion. Traffic calming solutions improve safety, reduce speeds, and prevent crashes every day.
An FHWA study on speed reduction found that the 85th percentile speed was reduced by an average of 18% with speed humps, 19% with speed cushions, and 18% with speed tables.
Research abounds on the effectiveness of speed humps and other traffic calming methods in reducing speed and improving safety. The American Journal of Public Health found that children who live within a block of a speed hump have significantly lower odds of being struck by a vehicle. The Journal also found a 53-60% reduction in the odds of injury or death for children with traffic calming in their neighborhoods.
Slower cars save lives
Does slowing cars just a few miles an hour really make a difference? View the survival chance (%) of pedestrians when a vehicle is travelling at the following speeds:
Vehicle Travelling at 20 mph 90%
Vehicle Travelling at 30 mph 50%
Vehicle Travelling at 40 mph 10%
Radar Sign Effectiveness
They’re easy to install, brightly lit, and can flash at drivers who speed. But do they work? In short, yes. Radar speed signs really do slow cars down. And slower cars have been proven to reduce accidents and decrease impact when accidents happen.
When cities use speed display signs they can expect to see reduction in average speeds, better speed limit compliance, and even long term reduction in speeding drivers and average speeds.
Here’s some sample data of the way speeds were affected after SafePace signs were installed on a local roadways.
Some studies that prove just how effective driver feedback signs are include:
A landmark study from Bellevue, WA which concluded that “At the majority of radar sign locations, results show an overall reduction of vehicle speeds between 1 and 6 mph, even up to 8 years after the signs were installed. Due to this level of effectiveness, the City will continue to use stationary radar signs….. to address vehicles speeds and/or….. motorist’s attention…..”
•In South Dakota the percentage of speeding vehicles was reduced by 20-25% •In Riverside, CA, drivers slowed by approximately 6 mph near speed trailer •In South Korea, speeders were reduced from 27% to 10% with speed signs •In Santa Barbara, CA average speeds were reduced by 10% •In work zones, signs reduced the number of speeding truck drivers by 24%
An evaluation by the Texas Transportation Institute of speed display trailer use in work zones found that the signs reduced average speeds by around 5 mph and were well liked by construction workers who felt that they “increased awareness of the work zone and significantly lowered speeds in the activity area.”
A study by the Texas Transportation Institute found that driver feedback signs “significantly reduced vehicle speeds at a school zone.…the average speed decreased more than 9 mph… [even] four months after installation.”
Research quoted in Wired Magazine found that radar speed signs “have proven to be consistently effective at getting drivers to slow down- reducing speeds by about 10%, an effect that lasts for several miles down the road.”
A study conducted by the Maryland State Highway Administration of speed signs in work zones found that the display trailers reduced average speeds by 2-7 mph and increased speed limit compliance by 10-40%.
Want to read more about how SafePace signs will change the way people drive on your streets? Take a look at some success stories here.
The faster a vehicle is traveling, the more damage is done to a struck pedestrian. 5% of pedestrians would be killed if struck by a vehicle traveling 20 mph, 40% at 30 mph and nearly 100% at speeds over 50 mph.