Canton Township police spokesman Sgt. Mark Gajeski said Friday there was no indication that alcohol or anything else was involved "other than bad judgment" in Thursday's crash about 20 miles west of Detroit.
Gajeski said he expected that toxicology tests would be done by the medical examiner's office. A message seeking comment was left with the medical examiner's office.
Authorities say 19-year-old Dan Broughton of Woodhaven was driving with a suspended license. A person who answered the telephone at a listing under the name said his family had no immediate comment.
Records from the Michigan Department of State show Broughton had a number of traffic violations, including speeding and disobeying a stop sign in the Detroit enclave of Highland Park on Jan. 7. His failure to show a driver's license April 1 in Woodhaven led a judge to suspend his license for one month on June 17 - a suspension that began Wednesday.
Authorities planned to release more information Friday on the victims, a copy of surveillance video from a nearby business that captured the crash and audio from a 911 report of the crash.
Investigators said the crossing had a gate and flashing lights that were working when the car approached. Police said the train, which was carrying about 170 people, typically travels about 67 miles per hour at the site of the crash. It broadsided the black Ford Fusion and pushed it about a mile down the tracks.
The mother of 14-year-old Jessica Sadler said Thursday the girl was among those killed. And police previously said the young men killed also included an 18-year-old and a 20-year-old from Taylor and a 21-year-old from Stafford, Va.
No one aboard the train was injured, Amtrak said.
Last year, 119 people died nationwide in Amtrak accidents, usually when trains struck vehicles or pedestrians at railroad crossings, according to figures from the Federal Railroad Administration. Eleven people died in train accidents of all types in Michigan in 2008, according to Federal Railroad Administration data.