By Scott Taylor,Staff Writer

Two of the busiest four-lane roads into the Twin Cities will be gone by next summer, if traffic engineers have their way.

Stretches on outer Lisbon Street in Lewiston and on Route 4 in Turner will be modified to three lanes. It’s a cheap way to make busy roads safer and slower, highway officials say.

Reducing travel lanes in other parts of the state has reduced the number of crashes at busy intersections and also has slowed traffic, highway officials say. They could not provide statistics to back up their assertions, but a 20-year study of Seattle roads showed a reduction in collisions and braking on realigned highways.

It also helps to solve problems caused by side-road traffic, a big problem on busy roads with many places for cars to turn left.

“We call it traffic friction, and that’s when people start to use the high-speed travel lane to turn or maneuver,” said Bruce Ibarguen, a state traffic engineer.

Most of the conflicts come between drivers intent on getting past the area and those trying to stop at businesses.

“Say you’re southbound on Route 4 and you want to go to the Irving,” Ibarguen said. Drivers now have to stop in the left-most lane of the southbound side, waiting for two lanes of northbound traffic to clear.

“So you have one eye on the northbound lanes, waiting for your shot, but you have the other on the rearview mirror, wondering if that guy coming up behind you is going to make it around you or not,” he said. “If you can get that turning traffic out of the flow, it greatly enhances safety.”

A new center lane does that, giving people driving in and out of businesses a refuge.

“Instead of two lanes of oncoming traffic to worry about, you have one,” Ibarguen said. It also gives emergency vehicles a safer place to drive while slowing down traffic overall.

The scheme is not new. The state relined a portion of Route 1A near Holden about 10 years ago, narrowing part of it to three lanes. They did it in Falmouth to a section of Route 1 around the same time. The city of Portland converted Brighton Avenue between Colonial Avenue and Rand Road to three lanes about four years ago.

It appears to work, said Peter Hedrich of Gorrill Palmer Engineering, the firm that helped design the Lisbon Street relining.

He pointed to a 1999 study by the Iowa Department of Transportation that compared results on six relined Seattle roads over more than 20 years. Those roads saw a 34-percent reduction in collisions.

“It also appears to reduce brake applications by 22 percent, according to national studies,” Hedrich said. Fewer conflicts means smoother drives through the area.

“When Portland did it on Brighton Avenue, they were looking to control the speeds in that area, and that’s what happened,” Hedrich said.

Mike Bobinsky, Portland’s public works director, said the city plans to do the same thing to Congress Street in two years.

“We’re looking at areas that have a mix of retail and commercial or residential, and we’re trying to slow down traffic without hurting volume,” Bobinsky said. “It’s a good way of doing that, giving it more of a neighborhood feel and making it less of an arterial.”

The three-lane option is also cheaper than adding a fifth lane to a four-lane road. That can get costly, Ibarguen said.

“On one hand, you have the cost of the grinding and the paint,” he said. “On the other, you have to buy up rights of way and design a new road.”

Grinding is set to begin today on Lisbon Street, said Chris Branch of Technical Services Inc., an Auburn engineering firm that designed the three-lane project.

Old paint will be ground off and new lines will reduce the four-lane road to three from the Lisbon town line to just under the turnpike overpass, about 1.9 miles. When the work is done, by about Oct. 26, Lisbon Street will have one lane eastbound, one westbound and a turning lane in the middle.

Plans for Route 4 in Turner call for two travel lanes and a center turning lane between Twitchell’s Airport and the Auburn line, about 1,500 feet. The state would like to do the work next spring. They’ve presented it the town of Turner and gotten a positive response.

“We have no problems, if it reduces traffic problems,” said Town Manager Jim Catlin.

The state plans to take its proposal before Turner residents, business owners and Route 4 commuters this winter.

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