The state Department of Transportation will close the westbound side of Memorial Drive at the Reid Overpass in Cambridge Wednesday at 8 p.m. for construction.
The portion of Memorial Drive over the rotary at the BU Bridge in Cambridge is expected to reopen by 4 a.m. Thursday, Oct. 3, according to the state.
The westbound side of the bridge will be closed to vehicles, cyclists and pedestrians, which will all be detoured to surface roads and then back onto Memorial Drive.
Transportation officials said in a press release Wednesday that the closure is necessary to install a bridge expansion joint.
Work has been ongoing at the Reid Overpass since April, but a closure of the bridge that was originally scheduled to last six months was reopened ahead of schedule in July.
Transportation officials are cautioning motorists traveling through the affected area of the closure tonight to expect delays and to reduce their speed.