State's proposed traffic 'roundabout' may send tiny Lisbon in circles

October 18, 1992|By Peter Jensen | Peter Jensen,Staff Writer

Some call it a traffic circle. Engineers prefer the term "roundabout." One mischievous patron at Lee's Market in Lisbon (population 129) has even labeled it the "Lisbon Beltway" on the flier that graces the deli counter wall.

Whatever you call it, the plan to build one at the intersection of Old National Pike (Route 144) and Route 94 is all the talk in this tiny western Howard County community: Some like the idea, many others do not.

"It's an experiment," says Dorothy Gray, a clerk at Lee's and a die-hard opponent. "If they put it in, I'm taking helicopter lessons and flying to work."

Just as Portugal's Lisbon was once one of the great centers for exploration four centuries ago, so too is Maryland's Lisbon, poised to become the starting point for a rediscovery of an old-fashioned approach to traffic.

The State Highway Administration's planned roundabout in Lisbon will be a first in Maryland. Never before has the state sought to create this kind of traffic circle along a highway, and if the Lisbon project proves successful, it could launch a trend.

Already, the state is studying a half-dozen other suburban locations where roundabouts could cure the problems of congested intersections.

Planners in Howard, Prince George's and Montgomery counties are looking at similar applications.

Advocates claim roundabouts are safer, more cost-efficient and more convenient than traffic signals.

"We've been considering it for years, but the concern has always been, will drivers accept it?" said Neil J. Pedersen, the SHA's planning director. "They've had them in Great Britain for years. The question is, can [we] adapt to that environment?"

Indeed, the notion of using a circle to steer traffic through an intersection is older than Vasco de Gama. Circles simply lost favor this century when the traffic signal went into widespread use.

Washington is filled with circles, routing traffic at major intersections throughout the capital city. But those examples are where modern roundabout advocates and planners of the past, such as Pierre C. L'Enfant, part company.

Unlike the District of Columbia's broad, multilane traffic circles, the roundabout is a smaller-scale effort. Cars are forced to travel at slower speeds of 10 to 15 mph, and there is less likely to be the notoriously fast-moving, weaving pattern of cars that Washington motorists have come to expect -- and dread.

The Lisbon roundabout,for instance, would be only 110 feet in diameter, including the landscaped island in the middle, with a single lane of traffic. Cars and trucks in all four directions would yield to vehicles in the circle before they could enter, not unlike a revolving door.

Consider the obvious advantages. In the technical lingo of planners, a conventional intersection with a traffic signal or stop signs has 32 points of conflict. That means motorists have to pay attention to many different directions -- cars coming from the left, right, and ahead, turning left or right, and on and on. A roundabout has only four conflict points: You yield to traffic before turning onto the circle.

The design yields a dividend in safety. Nobody can run a red light. The most severe accidents along any highway tend to happen when cars collide at high speeds head-on or at a perpendicular angle, an unlikely event in a roundabout.

"There is simply less chance of a major accident," said C. Edward Walter, Howard County's traffic engineering chief. "The worst you'll get in a roundabout is a side-swipe type of accident."

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

The Lisbon project appears to be an ideal opportunity to assess the potential benefits. It is expected to cost only $150,000, compared with the standard $75,000 price tag for a traffic signal.

Traffic in the current intersection is light, averaging 6,000 vehicles each day, but accidents have been a problem in the past. As recently as 1989, the crossing was classified as a "high" accident rate intersection with 40 accidents over the past five years, resulting in 49 people injured.

Under the current arrangement, motorists face stop signs on Route 144 only. So many drivers have run through the stop signs that the SHA added flashing lights two years ago, red on Route 144 and yellow on Route 94.

Still, state highway officials recognize that they will have to sell people in Lisbon on the idea of a roundabout before it can become a reality, and public opinion may be the greatest obstacle facing the project.

While roundabouts have become commonplace in Europe and Australia, they have yet to catch on in this country. Traffic planners have long believed that American drivers would resist the unfamiliar.

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