Although enforcement of speed limits by police departments is an effective means of reducing speeds, limited resources do not allow such enforcement on a regular and permanent basis. Research has shown that speed humps are an effective approach to slowing down traffic on residential streets. A speed hump is a gradual rise and fall of the pavement surface along the roadway extending across the pavement width. Generally, speed humps used on residential streets are 12 to 22 feet long with a maximum height of 3 to 4 inches. A speed bump is abrupt, having a height of 3 to 4 inches over a length of 1 to 3 feet.
Speed bumps cause most vehicles to slow down to almost a stop to go over it.
Speed humps, on the other hand, are designed so most vehicles can go over them at 20 mph without causing driver discomfort. A. Speed humps cause a gentle vehicle rocking motion that causes driver discomfort, thus resulting in most vehicles slowing down to 20 mph at each hump. Depending upon street geometry, speed humps are placed every 200 to 600 feet. The presence of speed humps causes drivers to slow down at the humps and in between properly spaced successive humps. Speed humps have the advantage of being self-enforcing.