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Speed Zones
Speed zones are often taken for granted and
until a problem arises, most people pay little attention to
the theory behind them. The following information will help
you understand how speed zones are established, and what they
can and cannot do.
Speed Zone Misconceptions
When traffic problems occur, concerned citizens
frequently ask why we don’t lower the speed limit.
There are widely held misconceptions that speed limit signs will slow the speed
of traffic, reduce accidents and increase safety. Most drivers drive at a speed
that they consider to be comfortable, regardless of the posted speed limit.
“Before and after” studies
have shown that there are no significant changes in average
vehicle speeds
following the posting of new or revised speed limits. Furthermore,
research has found no direct relationship between posted speed
limits and accident frequency.
Speed Laws
Almost all fifty states base their speed regulations
on the Basic Speed Law: “No person shall drive a vehicle…at
a speed greater than is reasonable or prudent…and in
no event at a speed which endangers the safety of persons or
property.” However, Tennessee is one of the exceptions.
Under Tennessee law, the maximum speed limit
on interstate highways is 70 mph. The maximum speed limit on
all other state routes is 65 mph. The Tennessee
Department of Transportation (TDOT) has the authority
to lower the above mentioned speed limits on the state system
of roads and highways.
Local governments may lower the maximum speed limits on roads and streets under
their jurisdiction. Local governments may also establish special speed limits
of not less than 15 mph adjacent to schools.
Speed limits between 15 and 65 MPH are established on the basis of traffic
engineering surveys. These surveys include an analysis of roadway condition,
accident records and a sampling of the
prevailing speed of traffic. A safe and reasonable limit is set at or below
the speed at which 85% of the drivers drive.
Traffic flowing at a uniform speed results in increased safety and fewer accidents.
Drivers are less impatient, pass less often, and tailgate less, which reduces
both head-on and rear-end collisions.
The posting of the appropriate speed limit simplifies the job of enforcement
officers, since most of the traffic is voluntarily moving at the posted speed.
Blatant speeders are easily spotted, safe drivers are not penalized, and patrol
officers aren’t asked to enforce and defend unrealistic and arbitrary
speed limits.
Speed Humps
Speeding on residential streets is a common complaint reported
by concerned citizens. Speed humps are often requested because they are perceived
as a quick and effective solution to speeding.
What are Speed Humps?
On public streets speed humps are 12 ft. long
by 3 in. high ridges of pavement placed across a roadway that
theoretically force cars to slow down as they pass over them.
They are intended to be uncomfortable to drive over if crossed
over too quickly.
Are Speed Humps Safe?
Several tests throughout the world on speed
humps have raised questions about their safety and effectiveness.
Their use has also been challenged under the Americans with
Disabilities Act. Test results indicate:
* Speed humps do not significantly reduce vehicle
speeds once the vehicle has left the speed hump. In fact, the
discomfort and shock sometimes decrease as vehicle speeds increase.
* Speed humps may present a potential hazard
to all vehicles including bicyclists, motorcyclists and emergency
vehicles.
* Speed humps cannot be designed to meet the
specifications for all types of vehicles because of the wide
variety of handling and ride characteristics.
* Traffic volumes on streets adjacent to streets
where the humps are located often increase when drivers try
to avoid the speed humps.
* Speed humps increase noise levels 10 to 20
percent when wheels hit the pavement. Increased noise is particularly
bothersome in residential areas.
Liability
Injuries caused by speed humps may result in
significant additional liability for the Town. Results of various
studies have raised concern about the non-effectiveness and
potential dangers of speed humps.
For these reasons, the Town of Collierville
does not use speed humps on public streets.
Reporting Speeders
To report unsafe drivers, please call the Collierville
Police Department at (901) 853-3207.
© 2006
The Town of Collierville
Website by Webz Media.
Content maintained by individual departments.
Every effort has been made to ensure the accuracy of the information
within this website. Please email the webmaster with suggestions
or corrections.
The
Town of Collierville does not discriminate on the basis
of race, color, national origin, age, sex, or disability in
its hiring
and employment practices, or in admission to, access to,
or operation of its programs, services, and activities pursuant
to Title VI
of the Civil Rights Act of 1964 (42 U.S.C. 200d) and the
Americans with Disabilities Act of 1990, Pub. L 101-336.
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