The congested commute along Route 175 in east Columbia is to develop a case of the bends starting at 9 p.m. today as traffic patterns change for the next phase of the huge task of building a $16 million interchange where the busy highway meets Snowden River Parkway.
Instead of driving straight through, with a long stop at the central cluster of traffic signals, vehicles will flare out several hundred feet on all sides, bypassing the old intersection.
With Maryland State Police on hand, the existing intersection will be off limits except to construction crews, and traffic will be guided by signs through the new maze of lanes.
"It's not really that big a deal. We're just going to divert the traffic around the intersection. It's a lot safer and easier to do it at night. It should be very simple," said Dennis March, area engineer for the State Highway Administration.
The crucial test, according to Howard County police traffic supervisor Sgt. A. J. Bellido de Luna, will come tomorrow morning and evening, during the rush hours.
"By starting at night we're going to know it will work before the heavy masses get into the area." No one expects serious problems, he added.
"It is going to be rather confusing the first time you go through it. That will be the main danger," he said. The greatest risk, he said, is that motorists slowing to look around could be hit by someone following too closely. By tomorrow evening, the heaviest rush, de Luna said the hope is that most drivers will have been through the intersection once already.
With the traffic gone, a crew of about 100 workers can begin excavating 20,000 square yards of earth for the main ingredient of the new interchange -- a bridge that will carry Route 175 over Snowden River Parkway, eliminating the need for traffic lights.
Temporarily, traffic signals will regulate vehicles on the detour roads, west of the intersection.
The project is five months behind schedule, but should be done next fall, a month or two later than originally expected, said March.
"We had to run an extra feed for power," March said, which meant ordering large new utility cables to go under the existing Park and Ride lot next to the Columbia Crossing shopping center.
The old utility cable feeding electricity to the traffic signals wasn't where it was supposed to be, and was badly deteriorated, March said. It had to be temporarily replaced and new cable ordered for the new lines -- which took months. When the project is done, there will be traffic signals regulating traffic entering or leaving Route 175, but not on the highway itself.
While waiting for the new cable, he said, the crews were able to do other work, so the finish date shouldn't be delayed for too long. And the delay has not affected the cost.
"Once we make this switch, things should start to roll real good," March said.
Henry Dagenais, chairman of the Long Reach Village Board, said the biggest change he's noticed lately is an increase in traffic on Snowden River Parkway since it was connected to the new Route 100 last year.
If the new changes slow things down a bit, it won't matter much, he said.
"I don't think it's going to slow traffic down that much more than it is now," he said.
Problem or not, the work has to be done, Dagenais said, and March is confident.
"Once people get used to it, it should be just like it was before."
State officials predict more than 75,000 vehicles a day will pass through the intersection by next year, and more than 92,000 a day by 2021.
De Luna said he has a personal, as well as a professional interest in the project.
"I go through that intersection several times a day. It can only get better. It can't get worse."