Highway cloverleafs are dying off; Heavy traffic, speed make many old ramps into danger zones

The cloverleaf -- the emblem of highway design for more than half a century -- is being snipped.

The graceful loops that once promised easy access to the nation's freeways have been overwhelmed by the speed and congestion of suburban traffic, creating a nightmare of crisscrossing motorists.


Now, as part of a nationwide search for safer alternatives, several Beltway cloverleafs will be pruned -- first at the Dulaney Valley Road interchange north of Towson.

"No one ever expected the growth in the automobile that we've had," said Tom Hicks, director of Traffic and Safety with the State Highway Administration. "The cloverleaf in the urban areas can't handle the traffic volumes."


A prime example is the cloverleaf at Dulaney Valley Road and the Beltway, which handles more than 177,000 motorists each day.

Drivers leaving Dulaney Valley Road and attempting to enter the Beltway must slow to 20 miles per hour to negotiate a downward curve -- then hope for a break between cars and tractor-trailers barreling down the Beltway.

During rush hour, Beltway traffic is packed bumper-to-bumper, making it even harder to ease out of the acceleration lane.

The answer, engineers say, is to eliminate two of the cloverleaf loops and replace them with left-turn lanes and signals on Dulaney Valley Road. The work is part of a $7 million overhaul of the intersection needed to accommodate a widening of the Beltway.

The first cloverleaf was reportedly built in 1928 at the juncture of Route 2 and Route 35 in the New York suburb of Woodbridge, N.J., easing the commute of workers into the city. Thousands of other cloverleafs blossomed throughout the country with the creation and growth of the interstate highway system in the 1950s and 1960s.

But while the four loops of the cloverleaf interchange allowed motorists to enter and exit freewayswithout stopping, they required cars to jostle for space in often short merge lanes. As traffic volumes grew in urban areas, it became increasingly difficult to get on and off the highways safely.

Highway engineers recognized the problem with cloverleaf intersections 30 years ago, but the push to eliminate cloverleafs has gained momentum in recent years.

"A lot of areas are struggling with it," said Alex Sorton, deputy director of Transportation Engineering Division at Northwestern University's Traffic Institute.


Throughout the nation, engineers are redesigning cloverleaf interchanges. Sometimes they are returning to left-turn lanes and traffic lights, such as at the Dulaney Valley Road interchange.

In other cases, they are taking the more expensive option of installing fly-over ramps, similar to those found at the triple-bridge overpass at Interstate 70 and the Beltway.

In New Jersey, which boasts the two oldest cloverleafs in the country, engineers are redesigning and enlarging the original cloverleaf in Woodbridge and dismantling the second-oldest, in Paramus.

That interchange at Routes 4 and 17 -- notorious for an average of 300 traffic accidents a year -- will be replaced with tiered ramps that will cost the state $120 million, said New Jersey Department of Transportation spokesman John Dourgarian.

In Maryland, meanwhile, the State Highway Administration redesigned two cloverleafs on the Capital Beltway three years ago, and officials now are looking to eliminate loops on several interchanges on the Baltimore Beltway.

The Dulaney Valley Road interchange will be the first cloverleaf redesigned in the Beltway makeover. Between 1994 and 1996, State Highway Administration officials counted 29 accidents on the Dulaney Valley Road interchange ramps. Two of the ramps had five or more crashes, which transportation officials called significant.


Engineers also expect to eliminate loops at the York Road interchange and possibly at U.S. 40 in Catonsville.

"The Baltimore Beltway was built in a rural area," Sorton said. "It worked great for a while. We didn't anticipate the suburban sprawl we've had."

Crews began the complicated task of overhauling the Dulaney Valley Road interchange earlier this month. The project includes a new, 264-foot bridge that will permit a future widening of the Beltway underneath.

The bridge, designed as a gateway to Towson, will include concrete molded to resemble stone found in the Towson area and lights and fences matching those on the Towson roundabout. The two-year project also includes a realignment of Hampton Lane.

Two loops of the cloverleaf will be closed when the project is complete. Then, motorists traveling south on Dulaney Valley Road and attempting to go east on the Beltway, will ease into new center lanes and await a traffic arrow that will allow them to turn left onto the Beltway.

Drivers on northbound Dulaney Valley Road who want to go west on the Beltway will have to make a similar move.


The left-turn lanes will eliminate the dangerous weave of traffic getting on and off the Beltway and make it easier for pedestrians and bicyclists traveling on Dulaney Valley Road, engineers say.

But as the orange and white construction barrels were placed earlier this month along the Dulaney Valley Road, local residents expressed fears that the traffic lights replacing the loops will lead to backups on Dulaney Valley Road.

"We were concerned that we see a potential for serious backups on northbound Dulaney Valley Road," said Thomas Orisich, vice president of the Hampton Improvement Association, whose community is also wary about the planned changes to Hampton Lane that they fear will make the road more dangerous for residents.

"They assure us this is going to work, but we have reservations," said Conrad Poniatowski, vice president and zoning chairman of the Dulaney Valley Improvement Association. "We have to have faith that they did their numbers properly."

Pub Date: 4/24/99