Updated at 1:21 p.m.

By Brian Arola

The Portland and Park Avenue bridges will be closed for construction throughout the summer, leaving both drivers and bicyclists without one of the main arteries into and out of downtown.

The bridges, which cross Interstates I-35W and I-94, will close May 6 and reopen in early August. The $5.7 million construction is meant to make the road surfaces smoother and extend bridge life, according to the Minnesota Department of Transportation, which is overseeing the construction.

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

Drivers should expect slower commute times along the popular routes, especially in the first days of construction, said Minneapolis Traffic Operations Engineer Steve Mosing.

“It will just be a matter of people figuring out their routes to get to and from downtown,” he said.

Detour routes (see graphic above) include taking Chicago Avenue from northbound Park Avenue and 3rd Avenue from southbound Portland Avenue.

Mosing said detours will also guide people to interstates, which will likely be the fastest alternate routes to and from downtown.

The bridges are also a popular route for bicyclists, as both avenues opened exclusive bike lanes in November 2012.

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 will be detoured to Chicago Avenue, which lacks bike lanes will get new striped bike lanes. Jensen said commuters should practice patience, as construction is a part of life in Minnesota.

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