BRENTWOOD -- The final piece of the Highway 4 puzzle here is set to be put in place this weekend.

Contractors with CC Myers/Bay Cities plan to do work the next few nights that will shift eastbound traffic on the freeway to a new alignment from Lone Tree Way down to Sand Creek Road.

The planned move will then allow westbound traffic to be switched over onto a bridge that passes over Sand Creek -- getting rid of a traffic signal that has caused local drivers angst over the years.

Come Sunday morning, drivers on Sand Creek in both directions will be able to hop onto Highway 4 using on- and off-ramps.

"It's really going to complete (the project) and make it wide open," Brentwood Mayor Bob Taylor said.

Traffic controls will be in place to allow work from 9 p.m. to 8 a.m. overnight Thursday and Friday and 10 p.m. to 6 a.m. overnight Saturday, Contra Costa Transportation Authority officials said in a news release.

The eastbound alignment will be completed by Saturday morning. The westbound shift will be done a day later, said Michael Scott, resident engineer on the project.

In late August, the $37 million project hit what local elected leaders and transportation officials called a milestone, when eastbound traffic was shifted away from the three-way signal at Sand Creek.

However, officials say they received several complaints from drivers since the switch about tie-ups near the Lone Tree on-ramp merger.

"This next set of shifts should alleviate those issues," Scott said.

Taylor added: "It's kind of been an obstacle. I keep assuring (drivers) it will be gone soon, and now that will be the case. It's exciting."

The gridlock along the stretch of Highway 4 often backed drivers up for miles, especially during the afternoon rush hour. Officials hope that frustration, along with concerns about safety, will be gone.

Plans continue to roll forward on a second bridge overcrossing at Sand Creek, which would push the point where highway traffic funnels from four lanes to two south of that road and allowing it to move smoother.

Recently completed design work is being reviewed by various Caltrans departments, Scott said.

Work to start creating dirt embankments for that bridge could start by mid-November, officials said.

When completed by the end of next year, Highway 4 will have on-ramps and off-ramps at Sand Creek and four lanes from Lone Tree south of Sand Creek.

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