The driver of a runaway bus that killed three people and injured 15 last month in downtown San Francisco was charged with three counts of misdemeanor vehicular manslaughter. The counts asserted negligence, but not the gross negligence that would have made the charges felonies. "Basically, there was nothing wrong with the bus," Police Inspector Robert Cardinale said. "It was driver error." He said driver Salvador Orogo, 53, could have stopped the San Mateo County Transit District (SamTrans) bus, but did not. The inspector said Orogo failed to use the brakes, take the bus out of gear or turn off the engine. Bail for Orogo was set at $10,000. Orogo was employed by Greyhound, which operated the bus under contract with SamTrans. After the accident, it was determined that Orogo had failed driving tests for employment given by three public transit agencies, including SamTrans.