What can cause the most harm to the environment?

Explanation: Engines are least efficient when they're cold; they take a few minutes to reach their operating temperature. Similarly, the catalytic converter needs to heat up before it operates efficiently. So, on short journeys, the vehicle will use more fuel and release more harmful exhaust gases into the environment. It may be quicker - and better for your health - to walk or use a bicycle.

Category: Band 1 road procedure

References: The Official DVSA Guide to Driving: Section 17