The United States Grand Prix was flagged to run behind a Safety Car on the opening lap on Sunday after a major collision involving German driver Adrian Sutil.
Sutil's Force India car was involved in a collision with the Williams car of Pastor Maldonado and hit the barriers heavily in an impact that damaged all four wheels.
Both men were unhurt and Sutil was fit enough to climb out of his car unaided.
The race started in heat-wave conditions at the Circuit of the Americas. The air temperature rose to 30 degrees and the track temperature was touching 40 degrees.
Newly-crowned four times world champion Sebastian Vettel led from pole position into an early lead ahead of Romain Grosjean of Lotus and Lewis Hamilton of Mercedes.