MADISON, Wis. -

Harry Weiss doesn't expect to get much sleep Wednesday night. Edward Kraemer and Sons Inc. is overseeing a construction project that is doing the unthinkable: shutting down the Beltline in both directions.

Weiss, the project superintendent, and a crew of about 10 workers will work through the night to set trusses across the Beltline. A new bike path overpass will span 360 feet across Madison's main drag at the cost of blocking off traffic on the highway for about seven hours.

"The bridge on top gets a concrete pad on top of it going all the way through," Weiss said. "And that's after everything steel gets set. We still have two other arches to set one on either side of the frontage roads and that'll be set around September 3."

Outside lanes in both directions were shut down starting at 8 p.m. Wednesday between Verona Road and Fish Hatchery Road. By 10 p.m., the entire Beltline will be blocked off to traffic. Work will cut off at 5 a.m. Thursday and the road will be reopened at that time.

The Cannonball bike path project is a multimillion dollar endeavor meant to connect bicycle routes and expand the 4.5 miles to help the commute across the Beltline.

Tony Fernandez is the city engineer heading up the project. He said there was no other option but to shut down the highway, and overnight was the most practical time to do it.

"We thought long and hard before doing this, but you can't really set a 150,000-pound truss over live traffic," Fernandez said.

Fernandez said according to traffic studies, that section of the Beltline sees about 130,000 vehicles every day. At the peak of evening rush hour, about 10,400 cars drive along the stretch that will have to be shut down. By 10 p.m., those counts went down to 4,300 to 4,800 vehicles. By midnight, that number dropped to 1,100 to 1,300 cars.

"Really in the long run, I mean, one night of lost traffic for a really nice infrastructure is really a small price to pay," Fernandez said. "It's going to be some inconvenience, but in two days it will be forgotten, and 50 years from now, that bridge will still be serving people."

Fernandez said under contract, work has to end at 5 a.m. Thursday. Crews plan to reassess progress around 1 a.m. to see if everything can be completed in one night. If not, Fernandez said westbound lanes could be shut down between Verona Road and Fish Hatchery Road again Thursday night.

While the clearly marked detours are out of the way, Fernandez did not expect this to cause too much of a disturbance for any overnight drivers.

"People won't be utterly stranded in that way, I don't think," Fernandez said.

Frontage roads will be closed in early September to install another set of trusses. The overpass construction is expected to finish up by early October.