Gov. Jerry Brown vetoed a measure Monday that would have allowed, during off-peak hours, all motorists to use carpool lanes on the 134 Freeway from North Hollywood to Pasadena, and on the 210 Freeway from Pasadena to Glendora.
The measure would also have allowed the state Department of Transportation to study whether similar openings should be used on other freeways in the county.
"Traffic congestion is always bad during rush hour, but there is no need for it to be bad during non-traditional commutes," Assemblyman Mike Gatto (D-Glendale) argued in favor of his AB 210.
Caltrans has long allowed solo motorists in Northern California to use carpool lanes after the morning and evening commutes are over.
That particularly comes in handy when other lanes are blocked by an accident or construction and the carpool lanes are largely unused, Gatto said.
However, Gov. Brown wrote in his veto message that he still has concerns that led him to veto a similar bill two years ago.
"I continue to believe that carpool lanes are especially important in Los Angeles County to reduce pollution and maximize the use of freeways," Brown wrote. "Therefore, we should continue to retain the current 24/7 carpool lane control."
The measure, which would have taken effect July 1, 2016, would have allowed Caltrans to decide which hours carpool lanes, also known as High Occupancy Vehicle (HOV) lanes, would be open to solo motorists.
Gatto was hoping the governor would have changed his mind, noting that since the last veto, Caltrans has completed a study finding that, for both freeways, "HOV lane usage drops substantially after the 6 p.m. hour."