Several Dallas city workers saved a colleague after his pickup truck plunged into a cold creek and stranded him in water up to his neck.
A bystander videotaped Tuesday's rescue as the workers broke a window of the water-filled cab to reach the driver.
Authorities are trying to determine if a medical issue caused him to lose control and drive into White Rock Creek on a morning when temperatures were in the 40s.
The workers were driving by, on their way to a job site, and noticed something in the water, then recognized it as brake lights of a city vehicle.
The video shows workers scrambling atop the swamped truck bed to reach the driver and float him to safety. The driver was submerged up to his shoulders.
A city spokeswoman said the employee was hospitalized Wednesday in serious condition.
Watch the video