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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.
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Temporary Installation
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Permanent Installation
Berkshire, England.
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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.
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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.
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Summary of Effectiveness
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Volume Reduction
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Unknown
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Speed Reduction
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Yes
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Safety Improvement
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Possible
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-
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-
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Streets to Use On Collector, Local
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Local/Collector
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Use on Bus Route
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Yes
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Use with Curbs and Gutters
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Yes
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Spot or Area-wide Use
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Spot
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-
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-
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Emergency Service Access Issues
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Less than Humps
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Impacts on Arterials
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Possible
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Change in % Trucks
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Unknown
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Environmental Changes
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Unknown
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-
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-
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Dependence on Enforcement
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No
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Level of Violation
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Self-Enforcing
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-
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-
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Aesthetics and Landscaping
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Can be Paved
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