Speed Cushions
Speed Table Dimensions: Length, Width & Ramp Specs
Cojo
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A standard speed table is 22 feet long by full-lane wide by 3 to 4 inches tall, with a 10-foot flat top and two 6-foot parabolic ramps. The Federal Highway Administration's Traffic Calming ePrimer Module 3.3 and the Institute of Transportation Engineers (ITE) Traffic Calming Manual, Chapter 3, specify these dimensions. Total length of 22 feet is what differentiates a speed table from a 12-to-14-foot speed hump and lets buses and emergency vehicles cross with minimal delay.
| Dimension | Standard value | Notes |
|---|---|---|
| Total length (travel direction) | 22 feet | 6-ft ramp + 10-ft flat + 6-ft ramp |
| Ramp length | 6 feet each side | Parabolic profile |
| Flat-top length | 10 feet | Sits 3 to 4 in above grade |
| Height | 3 to 4 inches | ITE-recommended range |
| Width (across travel) | Full lane | Curb-to-curb on most residential streets |
| Ramp running slope | 4 to 5.5% | At 3 to 4 in height over 6 ft |
The default profile. Each 6-foot ramp follows a parabolic curve from grade to the flat-top elevation. The 10-foot flat top is level (less than 1% running slope). This is the profile referenced in most municipal traffic-calming standards.
Replaces the straight-taper parabolic ramps with continuous sine-wave ramp profiles across the full 22 feet. The flat-top section is shortened or eliminated. The sinusoidal profile produces less vertical jolt for buses and emergency vehicles at the design speed and is preferred on transit and EMS corridors. Documented by the USDOT Volpe Center ride-quality research.
A 22-foot speed table that doubles as a marked pedestrian crossing. The flat-top section carries a marked crosswalk per MUTCD Section 3B.18 standards, and advance warning signs are placed per Section 3B.26. The geometry is otherwise identical to a standard parabolic table.
A 22-foot speed table with brick or paver inlay on the flat-top section. Asphalt structural slab plus 6-foot asphalt ramps. The inlay raises rolling resistance and provides architectural integration in historic districts. The geometry of the underlying structure is identical to a standard table.
Imagine looking at the speed table from the side. The road surface runs left to right. Starting from the left:
The full table footprint is 22 feet long. The car travels onto, across, and off of the device experiencing a smooth deceleration on the leading ramp, a brief level traverse on the flat top, and a smooth re-acceleration on the trailing ramp.
The 22-foot total length is what produces the difference between a speed table and a speed hump. A 12-to-14-foot speed hump compresses the vertical deflection into a shorter footprint, slowing buses to 8 to 12 mph. The 22-foot speed table spreads the deflection across more pavement, letting buses cross at 18 to 22 mph and emergency vehicles at near-posted speed.
ITE Traffic Calming Manual Chapter 3 documents this length as the result of bus and emergency-vehicle ride-quality research. The Federal Highway Administration's published bus delay measurements support the 22-foot specification: speed tables produce 2 to 4 seconds of bus delay per device, compared with 6 to 10 seconds per speed bump or 4 to 7 seconds per speed hump.
The 3 to 4 inch standard height is the same as a speed hump. ITE Traffic Calming Manual Chapter 3 documents this range as the height that produces meaningful 85th-percentile speed reduction (typically to 18 to 22 mph for parabolic tables, 20 to 25 mph for sinusoidal) while remaining within passenger-car suspension tolerance.
Heights below 2.75 inches do not produce reliable speed reduction. Heights above 4 inches violate ITE guidance and can damage low-clearance vehicles. Always verify current local jurisdiction requirements before specifying a non-standard height.
Where a speed table crosses an accessible route (sidewalk, marked crosswalk, or pedestrian path leading to a public entrance), the flat-top section must comply with ADA Standards section 403 running-slope and cross-slope limits.
| ADA constraint | Limit | Speed table compliance |
|---|---|---|
| Running slope on accessible route | Less than 5% | 6-ft ramp at 3 in tall = 4.2%, compliant |
| Running slope on accessible route | Less than 5% | 6-ft ramp at 4 in tall = 5.5%, fails |
| Cross-slope on accessible route | Less than 2% | Flat top is level, compliant |
The standard speed table spans the full travel lane width, curb-to-curb on most residential streets and curb-to-edge of opposing lane on collectors. Half-width or partial-width tables are not standard ITE configurations and are not recommended; they create asymmetric vehicle response and can promote dangerous lane-shift behavior as drivers attempt to avoid the device.
| Device | Length (travel) | Width (across) | Height | Notable feature |
|---|---|---|---|---|
| Speed bump | 1 to 3 feet | Full lane | 3 to 4 in | Parking-lot only |
| Speed hump | 12 to 14 feet | Full lane | 3 to 4 in | Slows buses |
| Speed cushion | 6 to 7 ft per segment | Segments + gaps | 3 to 3.5 in | Wheel-track gaps for fire trucks |
| Speed table | 22 ft (10-ft flat + 6-ft ramps) | Full lane | 3 to 4 in | Lets buses + EMS cross at 20 mph |
In April 2025 Cojo installed three sinusoidal-profile asphalt speed tables on a Eugene neighborhood greenway. The neighborhood association coordinated with Eugene-Springfield Fire Department on the profile selection; the sinusoidal geometry was specified explicitly to keep apparatus delay under 3 seconds at code-3 response. We field-verified the 22-foot total length and the sinusoidal cross-section against the engineering drawing before placing hot-mix, and submitted as-built dimensions on the close-out drawing to Eugene Public Works.
Always verify current requirements with your local jurisdiction. This article reflects May 2026 published guidance.
Cojo coordinates traffic-calming application packets and dimensional sign-off on every speed table install across the Oregon I-5 corridor. We document as-built dimensions on the project drawing and submit close-out documentation to the city engineering department. For the install procedure see how to install a speed table, and for engineering background see how do speed tables work. For Eugene-area installs see Speed Table Installation Eugene or pair installation with our asphalt maintenance services. Get a custom quote.
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