Speeding caused the horrific accident that killed an ex-EMS lieutenant and a young Staten Island man, sources said yesterday.

Benjamin Budzaku, 20, died instantly when he drove head-on into a private ambulance Monday night.

“He was going really fast, like flying!” said one source.

Ambulance driver David Restuccio, 58, had served 25 years with EMS and retired in 2006. He was a first responder at Ground Zero.

“Dave was a great teacher and passionate medic,’’ said Lt. Timothy Dluhos, who had worked with him.

Restuccio was recently engaged.