ST. IGNACE, Mich. (WJMN) – A detour allowing for installation of bridge beams south of the Mackinac Bridge has caused extended traffic delays for travelers on I-75.

The detour is part of a planned closure by the Michigan Department of Transportation (MDOT) from 8 p.m. Tuesday, July 26, through 6 a.m. Thursday, July 28 in Mackinaw City.

Mackinac County 911 & Emergency Management said in a Facebook post Wednesday that delays of up to one hour or more can be expected. The traffic delays include back-ups with heavy traffic congestion in the St. Ignace area (I-75 and US-2) trunklines to the Bridge.

During the closure, northbound I-75 traffic will be detoured on Nicolet Street (Exit 337) to Jamet Street (Exit 339). Southbound traffic will be detoured on Jamet Street (Exit 339), Louvigny Street, Central Avenue, and Nicolet Street to Exit 337.

Remaining work on the bridge will be done with single-lane closures on I-75 once the detour concludes.