Speed Bumps

Issues Posed

A speed bump is a bump of asphalt about a foot wide, three to four inches high, and placed laterally across the traveled portion of the road. The speed bump poses:

  • Cause of an undesirable increase in noise
  • Challenge to the daredevil
  • Disruption of the movement of emergency vehicles
  • An increased hazard to the unwary
  • Real problem for snow removal

Liability Suits

Because speed bumps have considerable potential for liability suits, Michigan has officially rejected them as a standard traffic control device on public streets.

Tests of Experimental Designs

Tests of various experimental designs have demonstrated the physical inability of a speed bump to successfully control the speeds of all types of vehicles. The purpose of a speed bump is to make the ride over it uncomfortable for drivers, thus encouraging them to reduce their speed. The driver of a soft sprung sedan can experience a more comfortable ride over a speed bump at a low or high speed, because of the vehicles' suspension system. On the other hand, a vehicle with tighter suspension (school bus, fire engine, moving van, etc.) must virtually stop before going over a speed bump.

Combating Speeding

Often these devices are suggested to combat speeding or "through" vehicles. If speeding is the alleged problem, studies must be conducted to determine the extent of the problem. Other, more effective steps can be taken to decrease the speeds of vehicles or the number of speeders. Often, there are a few speeders who cause most of the problems. If "through" traffic is the problem, it is often the symptom of a traffic-related problem on a nearby major street. The real problem should be determined, analyzed and corrected.

The control of speeding in residential neighborhoods is a widespread concern that requires resident compliance and patience, and persistent law enforcement efforts, not speed bumps.