It's been nearly 2½ years of navigating late-night road closures, narrow lanes with concrete barriers and lane shifts.

But Highway 4 drivers headed to and from work, particularly those who live in Pittsburg, will notice something else next month: a little less time behind brake lights.

The first two segments of the nearly half-billion dollar project to add more lanes on the freeway from Loveridge Road to the Highway 160 interchange are on track to be done by mid-December, with the completion of work on the westbound portion.

The eastbound lanes opened early last month.

"It's a sigh of relief," said county Supervisor Federal Glover of Pittsburg, who also sits on the Metropolitan Transportation Commission, the transit-planning group for the Bay Area. "That stretch has been a parking lot forever, so to see it continue to move, I think everyone is pleased."

Antioch resident Karleen Griffin said she's already noticed improvement.

Griffin, who drives to San Francisco for work several times a week, used to get off at Railroad Avenue to avoid sitting in gridlock.

"It's always going to be a little frustrating until the whole thing is completed, but it's so much better than it was. It's helping," she said.

The completion of the two segments will move farther east the point at Loveridge Road where rush-hour traffic has clogged for decades. Contra Costa Transportation Authority officials say having three through lanes and an auxiliary lane in each direction is a significant milestone.

"I think it shows that we're definitely making progress," said Randy Iwasaki, the transportation authority's executive director. "People are going to start noticing a big difference." County officials say work to this point is going smoothly and on budget. Much of the work removing old bridges and building new ones, adding retaining walls and expanding the roads is being done at night, so it doesn't affect commute traffic. Also, each construction segment is coordinated so that contractors don't overlap.

Among the factors aiding the brisk pace of construction is the lack of rain or poor weather, said Iwasaki, who lauded local drivers for their patience during the work.

That patience will continue to be tested in 2014. Next year will bring a lot of Highway 4 construction to most of the main thoroughfares in Antioch. Work on new bridges and intersections will take place at the Contra Loma Boulevard/L Street, Lone Tree Way and Hillcrest Avenue interchanges.

The work will include the demolition of the existing bridges over Contra Loma, Lone Tree and Cavallo Road, which will require more road closures at night. Highway 4 drivers will also have to brace for more traffic lane switches to make room for construction, including by Lone Tree Way in early spring, officials said.

The widening work includes creating a median in the highway wide enough for BART's extension into East Contra Costa County.

"We still have a long ways to go, but this is what we've been working toward for years," Glover said. "It's been a major undertaking."

In addition to the widening work through Antioch, a project to add onramps and offramps and add more lanes to Highway 4 by Sand Creek Road in Brentwood is on schedule to be wrapped up by the end of 2014. Work is also scheduled to start in the spring on connector ramps between Highway 160 and Highway 4.

All told, the $1.3 billion in East Contra Costa transit projects is arguably one of the larger, if not the largest, in the Bay Area right now, Iwasaki said.

The Highway 4 widening is scheduled to be completed by fall 2015, eBART two years later.

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

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

Where Things Stand
Here is the work being done on each segment of the Highway 4 widening project from Loveridge Road in Pittsburg to Highway 160, and status updates on the Highway 160/Highway 4 connector ramp project, the freeway widening at Sand Creek Road and eBART.
For updates on all Highway 4 work, visit http://4eastcounty.org.
Loveridge to Somersville: Work is being wrapped up on opening additional lanes of freeway traffic in both directions to Contra Loma Boulevard/L Street. It includes adding striping to roads, paving and electrical work.
Estimated completion date: December
Somersville to Contra Loma: Same as the Loveridge to Somersville segment.
Estimated completion date: December.
Contra Loma to Lone Tree: Concrete girders were recently set for bridges that will cross over Contra Loma Boulevard/L Street. Work continues on the bridge's foundation, adding lanes along the freeway and sound and retaining walls at various spots.
Upcoming construction includes demolishing the old Contra Loma bridge, setting precast girders for the new bridge, adding a permanent overhead road sign and continuing the new roads and sound walls.
Estimated completion date: Late summer 2015
Lone Tree to Hillcrest: Concrete was recently poured for the eastbound bridge deck over Lone Tree Way/A Street. Work continues on adding temporary supports, installing formwork and reinforcing steel for the bridge, and adding sound walls and retaining walls. Upcoming work includes removing the wall forms, and continuing work on adding the lanes and walls.
Estimated completion date: Late summer 2015
Hillcrest to Highway 160: Work continues to excavate land along the freeway for the additional lanes, and adding retaining walls, sound walls and drainage systems along the stretch. Columns are being added for the widening of the Hillcrest bridge. Contractors will continue excavating and adding the roadway structures, adding a concrete base and continuing work on the walls.
Estimated completion date: Winter 2015
Highway 4/160 Connector Ramp: A bid is expected to be awarded in December. Construction is slated to start in spring 2014.
Sand Creek Interchange: The construction of a freeway interchange at Sand Creek was completed last month. Work is set to start on building embankments for a second bridge overpass over Sand Creek Road.
Estimated completion date: Fall 2014
eBART: Contractors are building a parking lot at the Antioch station and the shell of a train maintenance facility, along with completing a transfer station in Pittsburg east of the Pittsburg/Bay Point BART station.
Estimated completion date: 2017
Source: Contra Costa Transportation Authority