Speed Bumps And Speed Humps

Speed Humps, according to this article in the American Journal Of Public Health, protect children from accidents.

Speed humps help protect children from accidents

Speed humps help make a child’s environment safer, according to a 5-year study of pediatric emergency department visits involving children struck by an automobile. In a study of children seen in the emergency department of Children’s Hospital Oakland from March 1, 1995-March 1, 2000, researchers found that those children living on or near streets with speed humps were less likely to be injured or killed by automobiles than children who lived on streets without such speed humps. Living within a block of a speed hump was associated with a roughly two-fold reduction in the odds of injury within a child’s neighborhood. Overall, living near a speed hump was associated with a 53-60 percent reduction in the odds of injury or death due to being struck by an automobile.
“These findings invite additional research on the protective effects of traffic calming interventions,” the study’s authors said. “Our study provides direct observational evidence that speed humps are associated with a reduction in the odds of childhood pedestrian injuries and supports installation of speed humps by traffic engineering departments.”
[From: "A Matched Case-Control Study Evaluating the Effectiveness of Speed Humps in Reducing Child Pedestrian Injuries." Contact: June M. Tester, MD, MPH, Children's Hospital Oakland, junetester@post.harvard.edu.]

This study appears to be based on surveying those injured in accidents.  It would be interesting to see the results of any additional scientific research projects.

I’ll continue to look for them and report them here as I find them. But “a 53-60 percent reduction in the odds of injury or death…” attributable to speed humps, is pretty stunning isn’t it?

A pair of designers Jae-yun Kim and Jong-Su Lee created a “smart” speed bump.  This speed bump actually reacts to the traffic that crosses over it.

A small damper built inside the speed bump flattens out the bump when slow moving traffic crosses over it.  On the other hand, the damper holds firm when a faster vehicle speeds over the speed bump.

This design makes the speed bump more emphatic to speeders than to non-speeders.

Read more here: http://www.yankodesign.com/2008/12/11/speed-bumps-that-flatten-for-slow-speeds/

There is a dramatic difference between “speed bumps” and “speed humps” but many people mistakenly use the terms interchangeably.

The simple difference between the two can basically be measured by the traffic calming affect of each device.

Speed bumps were designed to slow traffic from 0 to 15 mph.   Whereas speed humps slow traffic from 10 to 20 mph.

The way they fulfill their particular purpose is based on the cross section or the profile and the transition between the roadway surface and the device itself.

The speed bump profile is a more abrupt profile.  There is little distance between the roadway surface and the full height of the speed bump.  It can be compared to running over an object like a two by four rock in the middle of your tire.  This abruptness causes traffic to slow down to almost a stop before crossing over it.

On the other hand the transition between the Speed humps profile and the roadway surface is tapered and makes for a less abrupt transition between roadway surface and speed hump.   This is similar to running over a two by ten board with tapered edges. It causes you to slow down but not necessarily to stop.