"The guy jackknifed. Obviously it was too fast for the conditions," CHP Sgt. Mark Garrett said.
But Armendariz noted in her memo that the estimate was far from conclusive. A defense expert, she wrote, could use other simulator programs that might come up with different results and show that Reyes was not speeding.
Armendariz and district attorney's officials declined to comment on the investigation or elaborate on their decision not to file criminal charges. But her memo makes it clear that prosecutors concluded there were several reasons for the fatal accidents. The memo said the CHP investigator concurred with the prosecutor's decision.
An analysis of the right front brake on Reyes' 2004 Volvo led investigators to conclude that the vehicle was in an "out of service" condition, according to the prosecutor's memo. Photographs taken after the crash show a buildup of old grease around the wheel that could have prevented the right brake from grabbing as well as the left one.
Such a problem would cause the truck to veer to the left when a driver applied the brakes, Armendariz wrote. In fact, Reyes' vehicle did veer left when he lost control.
CHP officials believed that Reyes would have been able to see the safety problem when he conducted a required inspection of the vehicle before setting off. But prosecutors said the trucker could argue that the buildup did not become visible until he started driving or until after the crash, when the engine was dislodged and oil sprayed in all directions.
Howard A. Goldstein, an attorney representing a driver who was badly burned in the pileup and filed a lawsuit against the state and the trucking firm last month, said he was not surprised to learn that a braking failure could have caused the pileup. He said trucking companies often sacrifice safety in an attempt to cut costs.
"I see a lot of cases where there's a failure to maintain the truck," Goldstein said.
A spokeswoman for Georgia-based Saia issued a statement Tuesday saying that the company's vehicle had been regularly maintained and met state and federal safety requirements. The fatalities in the tunnel, she said, were unrelated to Reyes' accident.
"The tunnel is well known for being dangerous, with blind spots, curves and inadequate lighting," spokeswoman Sally Buchholz said in the statement.
