Officials will be targeting motorists who illegally pass stopped school buses in Fontana this week.
The California Highway Patrol says its officers will work with local police in an enforcement operation on Wednesday.
Officers will ride aboard buses, keeping watch for drivers who fail to stop for buses with flashing, red lights activated.
Offending drivers will be reported to officers in nearby patrol vehicles, who will stop the car to issue a warning or citation.
Violations are punishable by fines up to $1,000 and possible suspension of driving privileges.
The crackdown is meant to improve pedestrian safety, CHP said.
The agency says it was approached by the California Association of School Transportation Officials, which conducted a survey finding more than 26,000 drivers across 137 districts failed to stop for school buses loading or unloading students on a single day in 2016.
Drivers coming from both directions must stop for school buses with red lights are flashing, except on divided roads or multilane highways.
Yellow flashing lights on a school bus mean motorists should slow down and prepare to stop.