Freeway drivers commuting through North Concord and Pittsburg will see metering lights up and running Monday morning.
But, don't worry. There's some time to get used to the signals.
After two decades in the dark, all of the meters along Highway 4 and Highway 242 onramps will light up green starting Monday during commute hours, according to a Caltrans news release.
The meters will be on 6 to 10 a.m. westbound and southbound, and 3 to 7 p.m. northbound and eastbound.
Full-ramp metering, with lights going red to stop cars from merging, begins on Sept. 17 for the morning drive and a week later for the ride home.
"We want drivers to become acclimated with the lights and see they are working, while making sure that all of the wiring works properly," said Randy Iwasaki, executive director of the Contra Costa Transportation Authority.
In preparation, "Metering Begins" signs have been placed along Highway 4 from Solano Way to Railroad Avenue and Highway 242 from Clayton Road to Port Chicago Highway.
Engineers will be out the next few weeks inspecting how traffic reacts and determining if changes are needed to prevent backups into local traffic, Iwasaki said.
The addition of the signals during peak commute hours is aimed at improving traffic flow on one of the Bay Area and nation's most punishing commutes, according to local and regional transportation officials. The idea is to keep multiple cars from trying to squeeze onto the freeway at once, preventing a ripple effect of brakes from merging cars and reducing sideswipes.
There will be some delays as local drivers familiar with their current routine adjust to the new meters, said Jack Hall, an associate engineer with the transportation authority.
Caltrans has worked the past few months to repair the existing -- but never used -- traffic lights at Highway 4 entrances between Solano Way and Railroad Avenue.
The metering lights were installed in 1995, but Contra Costa transportation officials and local leaders balked at using the signals because of the potential for surface street backups where onramps are short and red lights are long. The county began studying ways to improve mobility in the area following approval of Proposition 1B in 2006 and along the Highway 4 corridor, with metering being one of the possible answers.
After months of public meetings, plans were given the go-ahead earlier this year.
Construction for the segment with the existing lights is about $900,000, according to the Metropolitan Transportation Commission.
County transportation officials also are looking at adding meters at Highway 4 entrances through Martinez and Antioch by the end of 2015, adding them in East Contra Costa as construction to widen the road moves eastward.
According to the county's implementation plan, metering lights would reduce the westbound Highway 4 drive time from Antioch to Alhambra Avenue in Martinez by 10 minutes, and the eastbound afternoon commute by nine minutes
All told, the project's total cost is about $27 million.
Contact Paul Burgarino at 925-779-7164. Follow him at Twitter.com/paulburgarino.