Drivers on Houston's Northwest Freeway witnessed a horrifying sight Wednesday night as a man fell to his death after clinging to the side of a moving tractor-trailer.

According to the Houston Chronicle, witnesses said an unnamed man dangled from the side of the truck, then fell off and was hit almost immediately by a pickup truck.

Police are still searching for the tractor-trailer and are trying to determine why the man was hanging onto it. Further details regarding the man's identity or condition were not available.