Construction begins Friday on the first expressway designed to connect Modesto, Riverbank and Oakdale, with county officials warning drivers to prepare for major detours.

The $184 million work, named the North County Corridor Project, will build a four-lane expressway along the Claribel Road corridor -- including new bridges over the Burlington Northern Santa Fe railroad tracks, Terminal Avenue and the Modesto Irrigation District canal.

Phase one of the project will close Roselle Avenue between Claribel and Plainview roads for up to a year.   

"This is a big deal for the locals. It's a big deal for Caltrans. It's a big deal for the region," Stanislaus County Public Works Director David Leamon said.

The county says the expressway will improve safety, eliminate traffic delays caused by trains and reduce congestion on local streets. Officials also expect the new corridor to allow bus service to run on Claribel Road for the first time.

"Right now, that road is so congested, so many trains, that they can't even run a schedule," Leamon said. "Once these grade separations are in, you won't be stopped by a train anymore."

Funding comes from a combination of Measure L sales tax dollars, state gas tax revenue and local development fees.

When complete in 2028, Phase One will stretch from Oakdale Road to Claus Road. Long-term plans call for additional phases extending the corridor to State Route 120 east of Oakdale, where State Route 108 would eventually be rerouted to bypass downtown Riverbank and Oakdale.

Drivers are being urged to use Sylvan, Oakdale and Patterson -- or Sylvan, Claus and Patterson -- to detour the work.