Smoke

The steam from the radiator is not smoke and does not mean that the car is on fire. Try to correctly assess risk.

In almost every serious traffic accident the radiator is punctured. Leaking coolant, together with the hot engine creates steam. 
If you do not see flames, do not worry that the car is on fire. If it's possible, secure the crashed vehicle against motion by pulling the hand brake and turning off the ignition.

During the rescue always be careful not activate airbags in the damaged car.