The Times asked some UC Berkeley researchers to look at Caltrans data, and they came up with a surprising conclusion: even though Orange Line ridership has been modest, with mostly empty parking lots, rush hour congestion has been lighter where the Ventura Freeway parallels the busway.

Traffic through the south San Fernando Valley from 7 a.m. to 10 a.m. has sped up about 7% — from an average 43 mph to 46 mph. And since the 14-mile busway opened Oct. 29, the amount of time that morning commuters waste being stuck in congestion — defined as traffic slower than 35 mph — has declined about 14%, the study found.

It also found that congestion on the heavily traveled freeway is now beginning about 11 minutes later than before the Orange Line opened, with the onset of the morning slows shifting on average from 6:55 a.m. to 7:06 a.m.

They only looked at Tuesday through Thursday commutes and excluded days when accidents affected traffic (and presumably aren't counting the blessed pre-Christmas easing I've noticed on many freeways.) They also found a paradox: more cars are using the Ventura per hour since the busway opened. "The freeway is operating more efficiently," said Hamed Benouar, director of the California Center for Innovative Transportation at Berkeley.