John Kaley, of New Britain, Conn, faces criminally negligent homicide, assault and other charges following the Friday night crash.
Nassau County Police Officer Michael Califano was killed when the 25-year-old Kaley's flatbed truck smashed into the rear of the police cruiser in Old Westbury.
He is also charged under a new law that requires drivers to move over if a police officer has someone stopped.
Kaley was held without bail after his arrest, but a judge Tuesday set bail at $47,500. Defense attorney William Petrillo said his client's thoughts are with the officer's family. He said the crash was accidental and not a crime.
A wake for Califano continues Wednesday, with a funeral mass set for Thursday morning in Seaford. Nassau County Legislators paused for a moment of silence for Califano Monday.
The criminal case against Kaley is moving forward, even as family, friends and fellow officers share their sorrow over the sudden death of the 44-year-old Califano.
Investigators say Kaley had fallen asleep behind the wheel. He suffered minor injuries, as did his fiancee, who was riding with him.
The National Highway Traffic Safety Administration says drowsy drivers cause more than 100,000 crashes every year. The toll is more than 1,500 people killed and 40,000 injured.