SPEED HUMPS, the latest development in speed control on county roads, are sprouting up in many of our neighborhoods, and they are proving effective.
These ripples in the road are 2 to 3 inches high and up to 22 feet long (in the direction of the traffic). They are smaller than the more familiar, vertebrae-altering speed bumps, which are 6 to 8 inches high and 8 to 16 inches long.
Unlike the more abrupt speed bumps, speed humps rise 3 inches in 6 feet, then are flat for 10 feet, then drop 3 inches in 6 feet.
"Speed humps are new to the county," said James Schroll, chief of the county's traffic engineering division. "And they're relatively new to the profession."
Speed humps are safer than bumps on public roads, he said, because they are less likely to damage a car than bumps are and less likely to cause a driver to lose control. Nor will the shock of hitting one throw workers from the backs of such vehicles as trash trucks or fire engines.
The faster a driver goes over a speed bump, the less it is noticed, Schroll said, but "you can't pass over a hump and not notice it."
"In terms of effectiveness, the humps are much better than the bumps," he said.
Speed humps have not sprouted up overnight. Montgomery County has hundreds of them.
Howard County has installed dozens of the humps in the past six years.
"We worked in this county for three or four years, experimenting with longer and lower humps," Schroll said. "Then we got permission to put one on Downs Road as a test case, to let snowplows and emergency vehicles drive over it."
The county put in three more test humps in the fall of 1995, then got permission to start a program of placing speed humps on county roads in communities that request them.
Before the county installs a hump, traffic engineers must determine that the road carries at least 1,000 vehicles a day and that 80 percent of the vehicles are traveling at least 10 mph above the speed limit.
If the traffic volume is 1,000 to 1,500 cars a day, the community that asks for the speed hump must pay the cost of its installation, about $28 per foot.
For example, a 20-foot hump would cost $560. If the traffic volume exceeds 1,500 vehicles a day, the county picks up half of the cost, Schroll said.
When you see SPEED HUMP printed on the asphalt and the signs are posted and the work trucks appear, be grateful.
For the price of a little inconvenience, your streets will be safer for you and your children.
Information: county traffic division, 410-222-7331.
Pub Date: 5/28/98