Jonathan McMaster ’12 thought he had left enough time to get to the Law School prom from his Prospect Street apartment Saturday night. He boarded a Yale Transit bus, and it began traveling down Huntington Street when the vehicle started accelerating downhill, reaching about 45 miles per hour. It hit the right embankment, swerved left, then jumped the curb.

McMaster, sitting in the sixth row, braced for impact; the other passenger, Aaron Dollar, an assistant professor at the School of Engineering and Applied Science, looked up from his phone from his seat in the second row. The bus then narrowly passed between a telephone pole and a large tree, missed two pedestrians and slammed into a parked car, driving the car into another tree.

After the impact, the driver turned off the ignition and he, McMaster and Dollar exited from the rear of the bus. No one was injured.

McMaster called 911 to report the crash, which occurred on the corner of Huntington Street and Edgehill Road. When the Yale police arrived after about 15 minutes, the driver t0ld the officers the brakes had failed, McMaster and Dollar said. After answering questions, both passengers were released by the police about an hour and a half later. During that time, a Yale Transit employee examined the bus and, McMaster said, declared it totaled. He also noted that the brakes seemed fine, McMaster said, and asked the driver why he had not applied the emergency brake.

McMaster said that during the bus’s acceleration, the driver had been slumped and looked asleep.

“The bus went limp like a dead fish. Nobody was driving it, and it was just coasting,” McMaster said. “I don’t think he woke up until we crashed.”

But Dollar thought the bus’s brakes had failed and credited the driver for both steering them safely between the telephone pole and tree, and stopping them with a relatively gentle collision.

“It could very well be that the driver saved our lives,” he said.

No representative from Yale Transit or Yale Police could be reached for comment over the weekend.

McMaster, who endured the 90-minute delay in his tuxedo, concluded that the experience taught him “to build in more time when trying to get to prom.” When he was released, another shuttle was called for McMaster, and he made it to the prom an hour and a half late.