BRENTWOOD -- Work to add an interchange here may be a bit hard on the ears of locals the next few weeks, but officials say it will be worth it for drivers.

The contractor for a project to add on- and offramps at Highway 4 and Sand Creek Road will be pile driving for the new undercrossing bridge the next two to three weeks, the Contra Costa Transportation Authority said in a news release.

The pile driving work began Monday. Work will be done from 7 a.m. to 5:30 p.m. Monday through Friday.

Nearby residents and businesses can expect increased background noise levels, the transportation authority said.

The $32 million project includes widening Highway 4 to four lanes from Laurel Road in Oakley to Sand Creek. Traffic on the stretch of the highway now back up for miles, particularly during rush hour.

The road work has also been adding to delays on the road.

For updates, call 925-206-3002 or go to www.ccta.net.

Contact Paul Burgarino at 925-779-7164. Follow him at Twitter.com/paulburgarino.