Speed Humps
Speed humps have been a very common traffic calming measure.
Speed humps represent one type of traffic calming measure that has been used by many local agencies for slowing traffic. Modern speed humps are 12 to 14 feet wide and have a rounded appearance that is 2.5 to 4 inches high at the center. Longer and flatter speed humps are referred to as speed tables. Speed humps have been shown to reduce motor vehicle speeds on streets where they were installed.[43] Despite their ability to reduce motor vehicle speeds, speed humps have certain disadvantages and are generally disliked by many drivers, fire departments and other emergency service providers. They often are not feasible on collector streets or arterial streets due to their impact on emergency response times. Other problems with speed humps include their impact on storm water runoff and snowplowing, and complaints about drivers driving onto the sidewalk to avoid the hump. The presence of speed humps also complicates street resurfacing.
While speed humps have been used extensively by some agencies, other traffic calming measures such as street-narrowing traffic circles or traffic diverters to eliminate cut-through traffic are often more effective and appropriate. Speed humps have been removed at some locations in the Netherlands and elsewhere in Europe and the United States.
Treatment: Speed Humps
Description/Purpose
An elongated section of raised pavement designed to reduce motor vehicle speeds. Longer and flatter speed humps are referred to as speed tables.
Expected Effectiveness
An overall reduction of motor vehicle speeds. More specifically, 85th-percentile speeds reduced by 4 to 23 mph.
Costs
Speed humps cost approximately $1,000 each. Speed tables range from $2,000 to $15,000 each (PEDSAFE, 2004).[3]
Keys to Success
- Selection of appropriate areas, which are primarily low-volume residential streets.
- Complete coverage of lane width to ensure drivers do not veer into bicycle lane to avoid the hump.
- Should not be used on sharp curves.
Key Factors to Consider
- Potential increase in noise.
- Potential drainage issues on some streets.
- Increase in cost and complexity of resurfacing.
- Appropriate design important to prevent motor vehicle passenger discomfort.
Evaluation Measures
- Number of crashes and motor vehicle–pedestrian conflicts.
- Motor vehicle speed and driver delay.