A speed bump and a speed cushion solve different problems. A bump is a continuous device that forces every vehicle to 5 mph — including fire trucks and ambulances. A cushion is a split-hump design with deliberate wheel-track gaps that let wide-axle emergency vehicles straddle while passenger cars hit it full-on. Pick the cushion when fire-apparatus access is a hard constraint. Pick the bump when it isn't.
Below: the two compared on dimensions, cost, fire-code compatibility, and the situations where each is the right answer.
Quick-answer comparison
| Factor | Speed Bump | Speed Cushion |
|---|---|---|
| Profile | Continuous parabolic | Split, with wheel-track gaps |
| Length in travel direction | 1 to 3 feet | 6 feet (typical cushion) |
| Width across the lane | Lane-spanning continuous | Two or three discrete pads with gaps |
| Wheel-track gap | None | 1.85 m (matches fire-truck axle) |
| Target speed | 5 mph | 15 to 20 mph for cars; ride-flat for fire trucks |
| Fire-truck response time impact | Slows to near-stop | Negligible (truck straddles) |
| Best location | Private parking lots | Fire-access streets, mixed-traffic roads |
| Typical cost installed | $200 to $1,500 per unit | $2,500 to $8,000 per unit |
What is a speed cushion?
A speed cushion is a split-hump traffic-calming device, typically built as two or three rectangular pads spaced across the lane width with gaps between them. The pads are 3 to 4 inches tall and roughly 6 by 6 feet. The gaps are sized to the wheel-track of fire-apparatus vehicles, typically 1.85 meters (about 6 feet, 1 inch).
The geometry produces an asymmetric effect. A passenger car, with a 1.5 m wheel track, cannot fit between the pads, so its tires hit one pad with each axle. A fire engine or ladder truck, with a 1.85+ m wheel track, places each tire in a gap and rides flat over the device.
This is the only vertical-deflection device that can be installed on a fire-access street without slowing fire response.
When should I choose a speed bump?
Choose a speed bump on private property where 5 mph is the target speed and emergency-vehicle access is not the binding constraint:
- Retail parking lot drive aisles
- Apartment complex internal roads
- Drive-thru lanes
- Single-family driveways
- Warehouse yards (heavy-duty rubber bumps)
For a hub overview, see our speed bumps guide.
A bump is wrong on a fire-access street, on a designated emergency-response route, or anywhere the fire marshal has flagged the route as critical for response time. ITE and FHWA both note that bumps add the most fire-response time of any vertical-deflection device.
When should I choose a speed cushion?
Choose a cushion when speed needs to come down but fire-truck access is a constraint:
- Designated fire-access streets in residential neighborhoods
- Multi-family complexes with fire-marshal access requirements
- Streets along ladder-truck response routes
- Mixed-traffic roads where buses and emergency vehicles share lanes with cars
- Neighborhood greenways where fire response time is a stated constraint
Portland's Bureau of Transportation uses cushions specifically on neighborhood-greenway routes that double as fire-access roads. The cushion is the only device that satisfies both the speed-management requirement and the fire-marshal sign-off. Salem and Eugene have similar policies on fire-access streets within their traffic-calming programs.
On a Tigard fire-access road install in September 2025, we placed three rubber speed cushions across a 0.3 mile residential corridor. Tualatin Valley Fire & Rescue measured response-time impact at less than 2 seconds per crossing, which the fire marshal accepted. The same corridor with bumps would have added 8 to 12 seconds per crossing.
What does each cost installed?
Industry Baseline Range — single-device install
| Component | Bump | Cushion |
|---|---|---|
| Material per unit | $80 to $1,500 | $1,500 to $5,000 |
| Labor per install | $150 to $600 | $800 to $2,000 |
| Traffic control | $0 to $200 | $400 to $1,200 |
| Pavement marking | $40 to $120 | $100 to $300 |
| Mobilization | $250 to $800+ | $400 to $1,000+ |
| Total installed | $200 to $1,500+ per unit | $2,500 to $8,000+ per unit |
Current Market Reality
Cushion installs in 2026 have run 30 to 45 percent above 2024 baselines because of fire-marshal sign-off requirements and traffic-control needs on active streets. The cushion product itself has stabilized in price; the increase is driven by the labor and permit components of the install. Bumps have been less affected.
What about emergency-vehicle response?
This is the design difference. ITE and FHWA fire-apparatus response studies show:
- Speed bump: Adds 8 to 15 seconds per crossing for a fire engine
- Speed hump: Adds 5 to 10 seconds per crossing
- Speed cushion: Adds 0 to 2 seconds per crossing
- Speed table (22 ft): Adds 0 to 2 seconds per crossing
For routes where fire response time matters, only cushions and tables are acceptable. NFPA 1141 (Standard for Fire Protection Infrastructure) and the International Fire Code Section 503 are the regulatory references your local fire marshal will use.
What about pavement marking and signage?
Both devices need yellow chevron paint, advance warning signs, and reflectors. The cushion needs additional signage indicating that the device has wheel-track gaps, since drivers approaching for the first time may try to position their car to straddle the gaps (which does not work for passenger-car wheel tracks).
The MUTCD W17-1 advance-warning sign is appropriate for both, placed 100 to 200 feet upstream.
Decision tree
- Is the site a designated fire-access route or emergency-response corridor? Cushion. Stop.
- Is the site a private parking lot with 5 mph target speed and no fire-access constraint? Bump. Stop.
- Is the site a residential street where transit vehicles run? Consider table instead. See speed bump vs speed table.
- Is the site a residential street with no transit and a 15 to 20 mph target? Consider hump instead. See speed bump vs speed hump.
- Is fire-marshal sign-off required for any reason? Cushion (or table) regardless of other factors.
For Oregon installs, including speed bump installation in Portland and full asphalt maintenance services, Cojo evaluates fire-access requirements and recommends the right device for each site.