|
SPEED
TABLES
Tops
can be paved for a more attractive look but this increases the
cost.
Example of Speed Table Sign
These are
basically flat-topped speed humps. If marked for pedestrian crosswalks
they become Raised Crosswalks. The most common is the 22-foot
design used by Seminole County FL. The ramps on the end are 6
feet long and the platform is 12 feet long. They have an 85th
percentile speed of 25 to 30 mph and present less of a "bump"
to drivers.
They have been used in Florida on roads with volumes up to 6,000
vehicles per day and are often used instead of speed humps. They
can be preferred by emergency response agencies.
Also known as Trapezoidal Humps and Speed Platforms.
|
Temporary
Installation
|
Permanent
Installation
Berkshire, England.
|
PROS
1.
Reduces traffic speed to 25-30 mph.
2. Less impact than speed humps.
3. Preferred by many emergency response agencies.
4. Often used in place of speed humps.
5. Relatively low cost measure.
|
CONS
1.
May impact emergency vehicles.
2. Care needed if placed on transit routes.
3. Not aesthetically pleasing though paving the top is
an option.
4. Avoid use on curved roads.
5. Noise may increase.
6. Care needed with drainage.
7. Avoid placing near driveway.
8. Need detectable ADA warnings.
|
Summary
of Effectiveness
|
Volume
Reduction
|
Unknown
|
|
Speed
Reduction
|
Yes
|
|
Safety
Improvement
|
Possible
|
|
-
|
-
|
|
Streets
to Use On – Collector, Local
|
Local/Collector
|
|
Use
on Bus Route
|
Yes
|
|
Use
with Curbs and Gutters
|
Yes
|
|
Spot
or Area-wide Use
|
Spot
|
|
-
|
-
|
|
Emergency
Service Access Issues
|
Less
than Humps
|
|
Impacts
on Arterials
|
Possible
|
|
Change
in % Trucks
|
Unknown
|
|
Environmental
Changes
|
Unknown
|
|
-
|
-
|
|
Dependence
on Enforcement
|
No
|
|
Level
of Violation
|
Self-Enforcing
|
|
-
|
-
|
|
Aesthetics
and Landscaping
|
Can
be Paved
|
|
