Twenty-two Foot Speed Bumps
Table 3: Typical Impacts of 22-foot Speed Bumps on Emergency Vehicles
Bureau of Traffic Management
Portland Office of Transportation
City of Portland, Oregon
January 1996
| Vehicle | Lowest Speed (mph) |
Desirable Speed (mph) |
Travel Time Delay (seconds) |
Impact Distance (feet) |
| Engine 18 | 21 | 25 | 0.8 | 136 |
| 21 | 30 | 1.7 | 323 | |
| 21 | 35 | 3.0 | 505 | |
| 21 | 40 | 5.0 | 752 | |
| Rescue 41 | 34 | 25 | 0.0 | 0 |
| 34 | 30 | 0.0 | 0 | |
| 34 | 35 | 0.3 | 118 | |
| 34 | 40 | 1.5 | 263 | |
| Squad 1 | 24 | 25 | 0.4 | 80 |
| 24 | 30 | 1.0 | 214 | |
| 24 | 35 | 2.1 | 433 | |
| 24 | 40 | 3.4 | 708 | |
| Truck 1 | 22 | 25 | 0.6 | 137 |
| 22 | 30 | 1.4 | 320 | |
| 22 | 35 | 3.0 | 600 | |
| 22 | 40 | 4.9 | 885 | |
| Truck 4 | 16 | 25 | 1.8 | 254 |
| 16 | 30 | 3.4 | 449 | |
| 16 | 35 | 5.9 | 674 | |
| 16 | 40 | 7.7 | 1039 | |
| Truck 41 | 14 | 25 | 3.0 | 316 |
| 14 | 30 | 4.8 | 622 | |
| 14 | 35 | 7.2 | 912 | |
| 14 | 40 | 9.2 | 1322 |
Lowest Speed: This is the lowest speed a vehicle travels when crossing a 22-foot speed bump.
Desirable Speed: This is the speed a driver might wish to travel if there were no speed bumps.
Travel Time Delay: This is the additional time required to travel to a destination due to a 22-foot speed bump's influence.
Impact Distance: This is the length of street where a given vehicle cannot be driven at a given desirable speed because of the speed bump's influence.