Howard controls traffic in 'roundabout' way Lisbon experiment leads to wider use of traffic circles EAST COLUMBIA

August 17, 1993|By Erik Nelson | Erik Nelson,Staff Writer

The traffic roundabout, which only last year was unknown to Howard County, is becoming a favored way of dealing with a variety of traffic difficulties in east Columbia.

County traffic engineers have decided to install two of the traffic circles on Old Montgomery Road, where the villages of Oakland Mills and Long Reach meet -- but for two completely different reasons.

One roundabout, at Oakland Mills Road, is intended to speed up traffic. The other, at Tamar Drive, is intended to slow it down.

"I think this thing is starting to catch on," said Doug Rose, district engineer for the State Highway Administration region that includes Howard County.

It was only this spring that the state convinced skeptical Lisbon residents to accept the temporary roundabout in Lisbon, the first of its type in the state.

Unlike the classic multi-lane traffic circles in Washington, the new roundabouts have only one lane and can be used both to slow traffic, in some cases, and to move it more efficiently, in others.

Motorists using the new, single-lane roundabouts must yield upon entering, making the roundabout operate much like a revolving door.

Because all motorists must merge into the same lane that goes around the roundabout, instead of crossing the path of other motorists, the system makes serious broadside collisions highly unlikely, engineers say.

The roundabout also is convenient. Traffic jams are often caused when cars must line up, waiting for a traffic signal. Roundabouts can handle a greater volume of traffic, reducing congestion and pollution from auto exhaust, according to engineers.

After receiving positive reviews in Lisbon, even from some who opposed the idea, the permanent roundabout probably will be installed there by late fall, said Mr. Rose.

The state now is considering installing a second Howard roundabout at Shaker Drive and Seneca Drive next to Allview Estates, to solve the problem of limited sight distance for drivers coming across the Shaker Drive bridge over U.S. 29.

County traffic engineers believe the concept will be just as useful on county roads as it is on state-maintained roads.

At one point, county officials even considered the possibility of installing four roundabouts at intersections around the Jeffers Hill Elementary School to slow speeders.

They have since decided to use only one roundabout, at Tamar Drive and Old Montgomery Road, which is expected to slow vehicles to below 20 mph.

Last spring, police had clocked some vehicles at 50 mph, said Ed Walter, chief of the county's traffic engineering division.

The county will supplement that roundabout with another measure, called a "raised intersection," which involves raising the entire intersection at Tamar Drive and Majors Lane three inches, like a giant speed hump.

The Tamar Drive roundabout, meanwhile, is still being designed. Final plans probably will be presented to the Long Reach village board at its Sept. 21 meeting.

Just a block away, the county's plans have progressed even further on the roundabout at the congested junction of Oakland Mills and Old Montgomery Roads, Mr. Walter said.

Currently, motorists going north on Oakland Mills Road have to stop at a stop sign, a condition the roundabout will eliminate, he explained.

"A roundabout at that location will give them more of an opportunity to get into traffic; it will give them less of a delay," Mr. Walter said.

The layout has been completed and engineers are beginning final design work. Mr. Walter said the roundabout should be built by next spring.

Lisbon's experiment in roundabouts has drawn attention from as far away as Washington County. It also has drawn intense interest from members of the Long Reach village board.

"This is what the county says will slow down traffic, and we would like to give it a try," said Kathryn Mann, Long Reach village's associate administrator.

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