Building work has begun on a £25m underpass in West Bromwich to cut congestion around the town centre.
It will divert the A41 Expressway underneath the existing fire station roundabout where it meets All Saints Way.
The scheme has been paid for by the Department for Transport and Tesco, which is building a new superstore in the town centre.
The project is due for completion by the end of 2011.
Sandwell Council said the project would revitalise the town and ease congestion on the busy expressway.
But motorists have been warned to expect major delays around West Bromwich town centre over the coming months.