A crash which closed State Highway One south of Timaru today is believed to have happened when a car crossed the centre line.
The police said witnesses reported the south-bound car crossed the centre line and collided head-on with a north-bound truck and trailer.
A 59-year-old man driving the truck escaped unharmed.
The 62-year-old man driving the car was trapped for about 40 minutes, and remained in Timaru Hospital in a stable condition with injuries to his legs.
The police said investigations into the cause of the crash were continuing.
The road is now open.