Investigators now say driver error is to blame in an accident that ripped open an ambulance, eventually costing an EMT her arm.

Clarkstown police say driver Scott Millar, 19, admitted that he was distracted when he got in the April 14 accident.

"He was ? looking at a GPS and when he looked up, he thought a vehicle was veering into his lane," says Clarkstown Police Sgt. Harry Baumann. "He swerved. Just so happened the truck was on the side of the road at the time and he hit the truck."

Millar crashed into a flatbed truck that was parked on Route 59 near the Palisades Center Mall. The impact caused the ambulance to tear open. Millar's fellow EMT, 21-year-old Bonnie Ames, suffered neck and back injuries. Her right arm was later amputated.

The driver of the flatbed truck had pulled over to make a cell phone call. Police say no tickets will be issued to the truck driver or Millar in accident.

The Mets held "EMT Night" Tuesday at Shea Stadium to benefit Ames. Part of the ticket sales will go toward her recovery.