Speed Tables

Typical Design:

• The most popular speed table is 22 feet in the direction of travel. Which includes 6-foot ramps on each side and a 10-foot flat top. The table is typically 3 to 4 inches high.
• Generally, the flat top of the speed table is long enough to fit the entire wheelbase of a car.
• The design speed is usually around 25 to 30 mph.
• Designs for speed tables with other dimensions exist. The dimensions of a speed hump best suited for a particular application are determined by desired design speed, wheel base of the design vehicle, and other specific design criteria.
• The speed hump can be integrated with the curb to create a crosswalk, or incorporate tapers by the gutters on each end to allow for drainage. The taper by the gutter is designed to not be wide enough for motorists to cross the table with one wheel in the gutter.
• The Institute of transportation Engineers has design recommendations.(2)
• The Pennsylvania Department of Transportation has design recommendations.(3)

The Flat-Top is a speed table.

Placement Issues:

• Speed tables can be used at mid-block locations.
• Fire trucks experience an approximate delay similar to that of a speed hump, 3 to 5 seconds per hump. The 22-foot table design seems to create slightly shorter delays than the 12-foot speed hump.(2)

Approximate Cost:

• Installation cost of a speed table is about $500 more than speed hump, $2,000 to $4,000. The cost can be much higher when drainage, brickwork, stamped asphalt, concrete ramps, and other features are added. With added features the cost can approach $10,000 per speed table.(2)

Comments:

• To attract attention and improve appearance the flat tops of speed tables are typically constructed with brick or other textured materials. This can attract attention to them and improve the appearance and possibly performance.
• The ramps can be constructed of concrete or asphalt.
• Currently speed tables appear to be a preferred over speed humps in parts of Florida, Georgia, Texas, and MD: some fire departments prefer speed tables over speed humps, speed tables appear to work better on roads that require higher volume and speed, and speed tables can be used as crosswalks where appropriate.(2)
• The aesthetics of the speed table should be considered in the design.