A 40-year-old Arundel man was killed Friday night in Kennebunk when his moped left the road and struck a guardrail, police said.

Andrew Giles was traveling west near 62 Old Port Road at about 9:45 p.m. when he crashed and was thrown from the moped, police said. Giles was not wearing a helmet.

“It is unclear whether a helmet would have saved this man’s life in this crash, but we always advise people to wear helmets whether on a bicycle, moped or motorcycle,” said Kennebunk Police Lt. Eric O’Brien.

The crash remains under investigation.