DETROIT – Four people looking at Tesla cars outside of the Shinola headquarters in Detroit were run over by a truck, seriously injuring one man.

Witnesses tell WDIV Local 4 the driver crossed the center line and, at a high speed, slammed into the people.

The witnesses said three people were hit by the truck and flew into the air, including a 73-year-old man who became wedged beneath an air stream. The 73-year-old victim suffered a serious head injury. Two women injured in the crash are listed in temporary serious condition.

A fourth person who was injured declined medical treatment and appears to be OK.

The 42-year-old driver is in custody and undergoing a blood draw to test for alcohol and drugs, police said.

Police immediately responded to the scene and the three victims were taken to the hospital.

Detroit police and Wayne State police are at the scene investigating.

Shinola, a high-end watch and bicycle manufacturer, is located in Detroit's Midtown neighborhood.

Tesla was holding a "Tesla Explores" event outside of Shinola. The automaker is traveling across North America with a mobile gallery pulled by a Model X SUV. The trailer was retrofitted to showcase interior and exterior vehicle options.

Following the crash, Tesla reps at the popup event said Thursday evening the trailer, surrounded by police tape, was still open for tours.