Motorists south of Owatonna on Interstate 35 will encounter single lane traffic and periodic traffic delays in both directions in the work zone as construction workers begin replacing three southbound bridges, according to the Minnesota Department of Transportation.

Motorists will see the traffic switched to a single lane in each direction in the northbound lanes, which started after 6 p.m. Friday. Southbound lanes are closed until mid-September while three bridges are replaced. The Straight River Rest Area for southbound is closed during construction. The northbound rest area is under construction and is expected to open later in summer.

Traffic backups are likely on I-35, especially on weekends. Motorists can decrease traffic backup dangers and more efficiently through a merge point by using both lanes of traffic while approaching the merge.

MnDOT will have signs posted 10 miles out warning of the potential of I-35 traffic backups and will have flashing signals activated when backups are occurring to alert drivers of slower moving or stopped traffic ahead.

This is a two-year project to replace six I-35 bridges and four Highway 14 bridges south of Owatonna.

On I-35, bridges over the Straight River, Turtle Creek and the Union Pacific Railroad are scheduled for replacement. On Highway 14, bridges over the Straight River and the Union Pacific Railroad are scheduled for replacement. Bridges southbound on I-35 and eastbound on Highway 14 will be replaced in 2017. The adjacent northbound and westbound bridges will be replaced in 2018.

Traffic on Highway 14 east of I-35 will be switched to single lane in each direction in the westbound lanes in early May.

Lunda Construction Company is the prime contractor for the $29.6 million project.