Driver involved in deadly Livingston bus collision last year, faces several manslaughter charges

Fresno, Calif. (KFSN) -- Mario Vasquez was fatigued according to the CHP at the time of the deadly bus crash in August of last year. A new report says excessive work hours and shift changes could be to blame.

Vazquez faces four counts of vehicular manslaughter. He made one of his first appearances in court on Wednesday.

"The fact that there's information that Mr. Vasquez was fatigued-- there were witnesses who saw him weaving and there was some evidence that he used his cell phone, while not at the time of the collision, but throughout the drive that day," said Nicole Silveira, Merced County Deputy District Defense Attorney.

The bus split in two as it drove into a highway sign and killed four of the passengers inside.

Incident reports say Vasquez had changed his usual day shift to a night shift the day of the collision and worked 10 consecutive days prior to the accident.

Investigators say Vasquez also worked 14 hours on the shift prior to the accident. That is four hours more than the maximum time both federal and state laws allow.

Many of the victims involved in the crash were also interviewed--some claim they "heard trembling" and other's saying he was "going too fast".

The report also shows Vasquez had several violations on his driving record, including speeding, and operating a commercial vehicle without a commercial license.

The investigation says while Vasquez was not using a phone at the time of the crash. It shows he answered a phone call 10 minutes earlier.

Attorneys say Vasquez is ordered to surrender his passport during his next court appearance in September.