Northbound Interstate 35E was shut down Sunday evening at Exit 457 in Lake Dallas for an investigation into a five-vehicle crash.
Witnesses said that a Ford F-250 was going very fast and hit the car in front of it, causing a domino effect into three more cars, Hickory Creek police Cpl. Dylan Stone said.
Police said the driver of the Ford pickup was unresponsive and unconscious at the scene. The driver and the passenger, who also had serious injuries, were taken to Medical City Denton. The driver may have been under the influence of alcohol, according to Stone.
Several other people were transported for medical care, but there were no other serious injuries, he said.
The investigation is ongoing.