SAN ANTONIO -

A man died when he lost control of his pickup truck and crashed into a guard rail three times in southeast San Antonio early Thursday morning.

San Antonio police said Juan Jose Flores, 53, was traveling north on Interstate 37 and took the 410 West exit ramp when he lost control of his truck for unknown reasons.

Police said Flores' vehicle went over the retaining wall after the third impact and landed on its side in a grassy median.

Flores was not wearing his seatbelt and pronounced dead at the scene, police stated in an accident report.

San Antonio police said the cause of the crash remains under investigation.