PITTSBURG -- Local businesses and drivers will soon be able to breathe a collective sigh of relief as the Highway 4 widening project reaches what officials are calling a "major milestone" later this week with the completion of a new Loveridge Road overpass.

After being restricted to two southbound lanes and one northbound during construction, two lanes in each direction of Loveridge and an eastbound highway on-ramp will open Friday afternoon, according to a Caltrans news release.

To prepare for the northbound half of the bridge opening, the eastbound on-ramp to the freeway will be closed 5 a.m. to noon Friday and the eastbound off-ramp will be closed from 5 to 11 a.m., Caltrans officials said. Some other curb and lane striping is being done this week.

"We've been working on that bridge since the beginning of the widening," said Susan Miller, project manager with the Contra Costa Transportation Authority. "I think it's something very visible that drivers can see and notice that the work (on Loveridge) is almost complete."

Highway 4 widening work started in July 2010.

The final configuration, which will include two left turn lanes onto the freeway in both directions, should be completed by the end of the summer, officials said.

Businesses in the vicinity, particularly North Park Plaza and Loveridge Center, have been resilient while waiting for work to be completed, City Manager Joe Sbranti said.

"Businesses have been struggling and they want this to be over with," Sbranti said. "Hopefully things now will start to be increasingly lighter and lighter over the next few months."

Tony Propst, owner of Quizno's Subs in Loveridge Plaza, said his business "has been more valleys than peaks" since construction started. The shop's average number of customers -- and employees -- before 1 p.m. have both been cut in half, he said.

"It's put quite a damper on us," Propst said. "People are refusing to come this way anymore; they don't like the congested traffic and that it's unpredictable -- especially if they only have 30 minutes for lunch."

A recent trip to deliver sandwiches to Praxair, located a couple blocks and two traffic lights away, took him 20 minutes, he said.

Nevertheless, Propst plans on "plugging along" and is hopeful bridge completion will bring back more customers.

Some new businesses are starting to locate to North Park Plaza, while Motel 6 is now looking to remodel its Pittsburg location off the freeway now that work is almost done, Sbranti said.

Construction continues to widen Highway 4 from four to eight lanes from Loveridge through Antioch to the Highway 160 interchange, and from two to four lanes from Lone Tree Way to Sand Creek Road in Brentwood.

For more information, visit http://4eastcounty.org.

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