Speed Bump vs Speed Hump

Generally speaking, speed bumps have a travel distance of 1 to 3 feet, speed humps a travel distance of 10 to 13 feet.

How can you tell if you're crossing a speed bump or a speed hump? If your front wheels completely cross the obstruction before your rear wheels come to it, you're crossing a speed BUMP. If your rear wheels come to the obstruction before your front wheels are completely across, you're crossing a speed HUMP. For a two axle vehicle, speed bumps produce two distinct bumps in sequence, one for the front axle, one for the rear axle. On a speed hump, your front axle climbs, followed by the rear axle climbing, followed by the front axle descending, followed by the rear axle descening, to give what can be described as an undulating ride.

Speed bumps can be defeated in a vehicle with a soft suspension by driving fast across them. The axle's suspension quickly compresses, but is then off the bump before that compressive force overcomes the inertia of the vehicle body. This tactic won't work on speed humps because the vehicle is on the hump long enough for the compressive force of the suspension to raise the vehicle body.

The problem with the existing speed control devices on the Leaburg Dam roadway is not that they are there, but that they are of the wrong kind. In other words, we can have adequate traffic calming for the protection of EWEB personnel and pedestrians (however infrequent they are) without bringing the flow of traffic to a near halt.

Unfortunately, the manner in which the usage of speed bumps on the Leaburg Dam roadway was decided upon is perhaps best described by the first sentence of the paragraph below found at the bottom of page 2 in Updated Guidelines for the Design and Application of Speed Humps published by the National Association of City Transportation Officials (NACTO):

Speed bumps of varying design have been routinely installed on private roadways and parking lots without the benefit of proper engineering study regarding their design and placement. Speed humps, on the other hand, have evolved from extensive research and testing and have been designed to achieve a specific result on vehicle operations without imposing unreasonable or unacceptable safety risks

Would that EWEB had taken advantage of the research and testing mentioned in the second sentence of the paragraph above.




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