Less-Favorable Data Skipped in Report on Car-Pool Lanes

Orange County transportation officials in September rejected a consultant’s finding that car-pooling had increased only 4% on the Costa Mesa Freeway since the lanes opened in November, 1985, and publicized more favorable data instead, participants in the dispute said Tuesday.

Genevieve Giuliano, associate professor of urban and regional planning at USC, said she met with officials of the Orange County Transportation Commission several months ago to discuss the results of her study. As part of the research, Giuliano had collected questionnaires from 777 freeway users. They were identified through videotaping of license plates.

Giuliano said the commission staff insisted during the meeting that it would make its own assessment of the results.

Kia Mortazavi, car-pool project supervisor with the Transportation Commission, agreed that there had been a staff meeting with Giuliano in which he was not “comfortable” with Giuliano’s “assumptions” about the normal rate at which people form and disband car pools, a factor Giuliano used in concluding that only 4% of those who car-pool on the freeway actually represent a departure from commuters’ expected driving behavior.

Did Not Want Debate

“We didn’t want to get into a debate about assumptions,” Mortazavi said.

In September, the Transportation Commission staff reported that 57% of the car-poolers now on the freeway had not been sharing rides 2 years earlier, and that 95% of those cited availability of the car-pool lanes as the primary reason for car-pooling. The report also said 43% of the car-poolers now using the freeway had started sharing rides either on the freeway or elsewhere before a car-pool lane existed.

Giuliano said she had adjusted her findings to account for the normal turnover rate of car pools, as reflected in her study of a control group of commuters who had no car-pool lane to use during their home-to-work trips.

She said commission’s use of the 57% figure in showing formation of car pools is not wrong, but should not stand alone without an explanation that the figure includes new Orange County workers who previously did not need to use the Costa Mesa Freeway, some people who would form car pools even if a special lane were not reserved for them, and others whose ride-sharing is temporary at best.

Most car pools, Giuliano said, last less than 2 years.

Giuliano said her study was the most stringent car-pool examination conducted so far and that it proves conclusively that car-poolers other than those who would be sharing rides anyway are using the car-pool lanes.

“An HOV (high-occupancy vehicle) lane is hard to justify to the public if it merely provides additional convenience for existing car-poolers without reducing congestion,” Giuliano said. “A 4% increase is significant, given the fact that the car-pool lanes on the 55 (Costa Mesa Freeway) do not lead to a central downtown and free parking is provided to almost everyone at work,” Giuliano said, “so I’m somewhat surprised that OCTC didn’t feel comfortable using that perspective. . . . Maybe it’s because they have suffered so much from the controversial politics surrounding the issue and they just wanted to put it to rest.”