When carrying a heavy load
Check the vehicle handbook. This should give you guidance on the correct tyre pressures for your vehicle and when you may need to adjust them. If you are carrying a heavy load you may need to adjust the headlights as well. Most cars have a switch on the dashboard to do this.
B When the roads are slippery
C When the vehicle is fitted with anti-lock brakes
D When the tyre tread is worn below 2mm