What Do You Need To Know About Speed Bumps?

Speed bumps, sometimes called road bumps or undulations, are used in speed zones of 10-15 mph. They are often found on local streets or connecting roads where a smooth flow of traffic is required but speeding would endanger the safety of pedestrians. Playgrounds and school areas often use these in traffic management.

Speed bumps can cause a slight jolt in a car driving over them at the prescribed speed limit. If the car travels at an unsafe speed, the hump strikes the vehicle and its contents, causing occupant discomfort and cargo disruption. These obstacles usually straddle the lane in which they are located. In this way, vehicles are encouraged to pass both wheels over them, reducing the likelihood of bottoming out.

Speed bumps come in a variety of shapes and stroke lengths. These factors affect the discomfort experienced in a speeding vehicle. Stroke lengths vary from 3-20 feet. Any run length longer than the vehicle will only produce one up-and-down motion, while a run length shorter than the vehicle will generate two rocking motions for each set of wheels passing by. Speed bumps are usually placed in tandem to maintain speed reduction in long corridors.

These vertical deflections are not a good option for arterial roads, emergency routes, or any street where a car can easily drive over the shoulder to avoid a hump. As such, they are often installed in single or two-lane local urban environments with curbs and closed sewers. If speed bumps are installed in areas with shoulders, they are often combined with bollards or other barrier measures to keep cars from leaving the road.