From 1 October 2015 it will be illegal to smoke in a vehicle with anyone under 18 present. The new law will apply in England and Wales.
Both the driver and the smoker could be fined £50. The law applies to every driver, including those aged 17 and those with a provisional driving licence.
The law does not apply if the driver is 17 years old and is on their own in the car.
The law is changing to protect children and young people from the dangers of secondhand smoke.