A 28-year-old man is dead and a 32-year-old male passenger is in critical condition after their SUV slammed into the back of an 18-wheeler on the high rise in New Orleans early Monday morning.

The incident occurred around 1 a.m. on Interstate 10 West near the Downman Road on-ramp, according to New Orleans police.

It's unknown why the driver of the Mitsubishi Endeavor SUV crashed into the back of the Volvo 18-wheeler. The bridge was closed for more than four hours after the accident.

Blood and alcohol tests are pending, NOPD said, and the investigation is on-going.

The victims' identities haven't been released.