Drivers, bikers and pedestrians, be advised: Two busy roads between south Minneapolis and downtown will be rerouted for work on bridges starting Monday and lasting all summer.

Park and Portland Avenues S. will close to all through traffic between E. 15th Street and E. Franklin Avenue. The bridges, which cross Interstates 35W and 94, will reopen in early August.

The $5.7 million project is meant to make the road surfaces smoother and extend the bridges' lives, according to the Minnesota Department of Transportation, which is in charge of the construction.

The Portland Avenue bridge averages more than 13,900 vehicles per day, while the Park Avenue bridge sees more than 11,000 per day, according to city of Minneapolis traffic data. Both are high numbers compared with nearby roads.

Drivers should expect slower commute times along the popular routes, especially in the first days of construction, Minneapolis Traffic Operations Engineer Steve Mosing said. "It will just be a matter of people figuring out their routes to get to and from downtown," he said.

Detour routes include taking Chicago Avenue from northbound Park Avenue and 3rd Avenue from southbound Portland Avenue. The interstates will also be an option, and will likely be the fastest alternate routes to and from downtown.

Soren Jensen, the executive director of the Midtown Greenway Coalition, said the bridges were among the best routes into and out of downtown for bicyclists.

Bicyclists and pedestrians will be detoured to Chicago Avenue, which MnDOT will paint with bike lanes. Jensen said commuters should practice patience.

"Detours are a pain, but they just sort of come with the territory," he said.

Brian Arola is a University of Minnesota student on assignment to the Star Tribune.