A set of speed bumps planned for Manhattan Beach Road will give motorists a jarring reminder that they're back on their neighborhood's quiet streets.
Two other county roads will get the speed bumps as the Department of Public Works and county officials work to control traffic.
"We hope that this keeps speeds more in line with speed limits," said Andy Watcher, a county traffic engineer.
The speed bumps, raised concrete on top of the road surface, cost about $1,200 apiece, Mr. Watcher said. The bumps rise 3 inches during the first 6 feet, level off for 10 feet, then fall off 3 inches over the final 6 feet.
The first bump on Manhattan Beach Road will be a few feet south of Cypress Beach Road; the second, at the entrance to Locksley Court; the third, between Locksley Court and Raussel Place; and the fourth, just north of Oak Grove Circle. The final speed bump will be several feet north of Gordon Avenue.
Mr. Watcher said residents off Manhattan Beach Road approached public works officials in December 1993 and asked for help to stop traffic speeding through the neighborhood. Department studies showed drivers were going about 15 mph over the 25 mph speed limit.
Manhattan Beach Road is too narrow for islands. But the bumps also were preferred because they are cheaper -- by about $4,000, in this case, Mr. Watcher said.
The county hopes its project on Manhattan Beach Road will replicate the successes in Howard County. Average speeds there dropped 10 mph to 14 mph after the bumps were installed, Mr. Watcher said.
"What is really jolting to the driver is the decline part of it," he said. "It's a very jolting, jarring effect. I found that it was passable at 30 miles per hour. Anything faster is very uncomfortable."
Scott Wiley, a member of the Manhattan Beach Civic Association board, said many residents simply forget the change in speed limits between nearby Ritchie Highway and Manhattan Beach Road.
Mr. Wiley said residents unanimously approved of the bumps.
Work on Water Oak Point Road in Pasadena is scheduled for the end of this month. No date has been set for work on 220th Street