Is it legal to drive a car with a smooth spare tyre after getting a puncture?

The correct answer is that it is illegal to drive a car with a smooth tyre, even if it's the spare. In Australia, including New South Wales, the law requires all tyres on a vehicle, including spares, to meet certain safety standards. Smooth tyres do not provide adequate grip or traction, especially in wet conditions, increasing the risk of losing control of the vehicle. Safety regulations are in place to ensure that all tyres on a vehicle contribute to safe driving, and having a worn-out or smooth spare tyre compromises this safety, making it illegal to use in that condition.

In contrast, driving with a smooth spare tyre might lead to reduced safety on the road, particularly when emergency situations arise where proper tyre performance is critical. Therefore, ensuring that all tyres, including spares, are in good condition is essential for the safety of the driver, passengers, and other road users.