They first debuted in California in 1967 at the Sunrise Blvd on-ramp to the 101 Freeway in Los Angeles.
41 years later, they will make their first ever appearance on Stockton roadways.
"While ramp metering itself is pretty common in Southern California and the Bay Area, it's relatively new to San Joaquin County," said Cal Trans District 10 spokesman, Skip Allum.
Starting next Tuesday, the Mariposa Road on-ramp to SB 99 will be the first to test metering lights in Stockton.
Eventually, five other SB 99 locations will be added over the next several weeks.
They include Golden Gate Avenue/SR-4, Fremont Street, Waterloo Road, Cherokee Road and Hammer Lane.
The testing phase is expected to run to October. No dates have been added to test the northbound lanes of 99.
San Joaquin County's first metering lights went in about a year ago on the EB and WB 205 Freeway near Mountain House.
Cal Trans says the metering is to "manage the on-ramp flow of traffic to maintain an efficient freeway system."
Cal Trans adds that Stanislaus County drivers will see their first metering lights at Briggsmore Avenue in Modesto within a couple of months.
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