Narrowing | Lateral
/ Horizontal Shifts | Raised
Devices | Complementary
Tools | Whole
Traffic calming is a way to design streets, using engineering principles,
to encourage people to drive more slowly. It creates physical and
visual cues that induce drivers to travel at appropriate speeds. Traffic
calming is self-enforcing. The design of the roadway results in the
desired effect, without reliance on enforcement or voluntary compliance.
Traffic control devices such as signals and signs rely on compliance.
While elements such as landscaping and lighting do not force a change
in driver behavior, they do provide the visual cues that encourage
people to drive more slowly.
The reason traffic calming is such a powerful and compelling tool
is that it has proven to be so effective. Some of the goals of traffic
calming are clearly measurable such as increasing safety through fewer
and less severe crashes. Others such as supporting community and livability
- are less tangible but equally important.
Numerous studies throughout Europe, Australia and North America have
shown that traffic calming reduces traffic speeds, the number and
severity of crashes, and noise levels. In the Netherlands, an evaluation
of 44 redesigned roads found a 72 percent reduction in the frequency
of crashes. Extensive studies in Germany, France and Britain show
speed and/or crash reductions of 30 percent-53 percent.7 In Vancouver,
BC, an analysis of traffic calming in four neighborhoods quantified
the substantial economic benefits arising from fewer crashes. These
included reductions in police, fire, hospital, and insurance costs.
Conversely, higher speeds have a negative effect: an increase in the
average speed of motor vehicle traffic by 1 km/hour increases the
number of injury crashes by approximately 3 percent and increases
crash related costs by approximately 6 percent.
There are certain overall considerations that are applicable to both
traffic management and traffic calming:
In terms of safety, speed is more critical than volume and
should be addressed first where there are monetary constraints.
Neighborhood involvement is important to successful
Traffic calming and management measures should fit into and
preferably enhance, the street environment.
Traffic calming and management measures should make sense.
Traffic calming designs should be predictable rather than random,
and easy to understand by drivers and other users.
Devices that meet multiple goals are usually more acceptable.
For example, a raised crosswalk is more understandable to motorists
than a speed hump. The former has a clear goal whereas the latter
may be perceived as a nuisance.
This midblock crossing is in Kalamazoo, Michigan. The landscaping and textured crosswalk are visually appealing and provide a clear message about where pedestrians can be expected to cross the street.
Devices need to be well designed and be based on current available
information on their applications and effects. Information of U.S.
experiences with various traffic calming measures are found in ITE’s
“Traffic Calming: State of the Practice.
Traffic calming areas or devices should be adequately signed,
marked and lit to be visible to motorists.
Devices need to be spaced appropriately to have the desired
effect on speed - too far apart and they will have limited effect,
too close and they will be an unnecessary cost and annoyance. Devices
usually need to be spaced about 300-500 feet apart. If they are spaced
too far apart, motorists may speed up between them. This is particularly
the case where the devices are added onto the street, e.g., speed
humps. Whole street designs are usually able to create an environment
that supports slower speeds for the entire length.
Devices should not be under–designed, or they will not work.
Keeping the slopes too gradual for a speed table or curves too gentle
for a chicane will not solve the problem and will appear as a waste
of money and may ruin chances for future projects.
If a measure is likely to divert traffic, the area-wide street
system should be considered so as not to shift the problem from one
place to another.
Traffic calming tools may be used in combination, and are often most
effective this way. The tools in this guide are organized into the
Some tools fall into multiple categories, but for simplicity are listed
Trials and Temporary Installations for Traffic Calming
In communities trying traffic calming for the first time, it may be useful to lay out a new design with cones or temporary markings to test it. This provides emergency vehicle drivers, residents and others with an opportunity to test the design to assure that they are comfortable with it. Some communities have constructed elaborate temporary devices with concrete (“jersey”) barriers, or plastic barriers. These can instill a negative reaction in the community due to their unaesthetic nature. They do not generally have any significant benefits over the simpler test run devices, and it is better to go straight to a final product, which is more appropriate for a neighborhood setting.
The material provided on this page is from the FHWA publication
"Pedestrian Facilities User Guide." This guide is currently under review
by practicioners and others in the field. Subsequently, the material
provided on this page is subject to change in the future.
Institute of Transportation Engineers has arrived at the following
definition of traffic calming, which is often used in the United
calming is the combination of mainly physical measures that reduce
the negative effects of motor vehicle use, alter driver behavior
and improve conditions for non-motorized street users
TRAFFIC CALMING WEB SITE:
The Federal Highway Administration inaugurated a new Web site dedicated
to all the known and/or electronically publicized transportation programs
and studies that pertain to traffic calming.
The site provides:
general objectives of traffic calming
to traffic calming programs
links to other related agencies
A list of recent studies
list of any upcoming events
intake page for reader feedback and contact information
calming improvements need to include input from and coordination with
neighborhoods which are impacted