ANTIOCH -- Though construction on Highway 4 continues, East Contra Costa commuters have probably noticed a reprieve the past few months from the overnight road closures, traffic lane shifts and the "cone zone."

That will soon change.

Detours for drivers will rev up in earnest next month between the Contra Loma Boulevard and Hillcrest Avenue exits, as old interchange bridges at Contra Loma and A Street will be demolished and newer, wider ones will be built.

Traffic lane shifts to accommodate the moves will start in mid-June, said Ivy Morrison, a Contra Costa Transportation Authority spokeswoman for the project. Most of the work will be done at night so as not to hinder commuter traffic, she said.

More overnight road closures are coming to Highway 4. (Dan Rosenstrauch/Bay Area News Group)
More overnight road closures are coming to Highway 4. (Dan Rosenstrauch/Bay Area News Group)

It's been four years since work started to expand Highway 4 from four lanes to eight from Loveridge Road to the Highway 160 interchange. The half-billion dollar project, scheduled to be completed by fall 2015, will include creation of a median in the highway wide enough for BART's extension into East Contra Costa County, dubbed eBART.

The widening project is about "50 to 60 percent complete," said Ross Chittenden, the agency's deputy executive director.

Work through Antioch over the past few months has included completion of a bridge over G Street, adding soundwalls and clearing the ground for new lanes along Highway 4 from Contra Loma east past Hillcrest.

Road construction also started this spring on Antioch's eastern border, with large cranes driving piles and heavy machinery moving dirt in preparation of adding connector ramps from Highway 160 to Highway 4.

That project, which came about thanks to $50 million in bridge toll money remaining from the Antioch Bridge retrofitting, will require some upcoming overnight road closures.

Completion of the freeway widening from Loveridge Road to Contra Loma Boulevard has helped move traffic and get commuters home quicker after work, officials said.

Road detours are "a part of doing business," said county Supervisor Federal Glover, of Pittsburg, who also sits on the Metropolitan Transportation Commission, the transit-planning group for the Bay Area.

"I think drivers realize there have to be some closures and some pain. But the type of relief we're now experiencing makes it a bit more tolerable," Glover said.

Chittenden added: "It's already had a dramatic effect, especially for the morning commute. It's made getting to Loveridge easier, and Somersville to a certain extent."

The next series of detours should be a bit easier on drivers because there will be fewer "S-curves," Chittenden said.

The same contractor is working on all three portions of the freeway, so instead of having coordination issues between two companies, it can be engineered as a larger project, he said.

"From a travelers standpoint, there will be less lane shifts and longer shifts," he said. "There will be more noticeable progress, and it will be less abrupt."

Highway 4 contractors will also start work in mid-June on the entry house and overcrossing for a new Antioch BART station located just east of Hillcrest Avenue, Morrison said.

"When work in the median starts in the fall, it will become very apparent to the community," she said.

eBART is anticipated to be completed by late 2017.

For updates on all Highway 4 work, go to http://4eastcounty.org.

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