Speed bump
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A speed bump (in British English sometimes a sleeping policeman) is a traffic calming measure. It consists of a bump in the roadway, designed to cause oncoming vehicles to slow down in order to pass safely. Speed bumps may be circular, parabolic, or sinusoidal and have gaps near the curb to allow drainage. The speed at which a bump can be taken safely decreases with its slope. Their height ranges from as short as 2 inches to as tall as 6 inches, and can vary in length from as short as 1 1/2 feet (in the direction of travel) to as long as 10 feet. Speed bumps that are greater than 10 feet in length are a variation usually called speed humps and are used to slow traffic in residential neighborhoods.
The use of speed bumps is widespread worldwide, and are most commonly found in parking lots, alleys, and other places where prevaling vehicle speeds are expected to be low.
Although speed bumps are very effective in keeping vehicle speed down, their use is somewhat controversial as they can cause vehicle damage and even passenger injuries if taken at too great a speed. Some are hard to negotiate in vehicles with low ground clearance, such as sports cars, even at very slow speeds. Poorly designed speed bumps (too tall, too sharp an angle for the expected speed) are often to blame, rather than the concept in general. Vehicles with high ground clearance and softer springing, such as sport utility vehicles and other nominally off-road vehicles, negotiate speed bumps much more comfortably even at greater speeds than regular passenger cars. Thus, there is some reason to believe that the prevalence of speed bumps encourages the SUV phenomenon, and certainly that phenomenon reduces the speed bump's effectiveness as a traffic calming measure.
Some speed bumps have been criticised as being an impediment to emergency vehicles, particularly ambulances, where EMTs may be working on a patient.
Other uses
- Speed Bump is the name of a comic strip by Dave Coverly.
- The term Speed Bump has come into use as a metaphor to describe an obstacle of minor significance which temporarily slows, but does not stop or continue to retard momentum or progress.
- (IE, "According to the latest reports, the political campaign of Senator Jane Doe was well on the road to her successful re-election until it encountered a speed bump last month when the expenses associated with her recent congressional fact-finding trip to Hawaii were questioned by her opponent. However, according to the Chairman of the Committee to Watch the Volcano For Safety Hazards, she provided documentation that all expenditures on the trip were legitimate expenses, and the public furor over the issue soon subsided after the Senator showed pieces of lava at a recent press conference.")