Tyres
Minimum tread depth is 1.6 mm for a car, across the central three-quarters of the tread and around the whole circumference. For a motorcycle over 50cc it is 1 mm.
Below the limit, a tyre cannot clear water and wet grip collapses. Each illegal tyre carries its own penalty, so a set of four is four offences.
Check pressures when the tyres are cold — at least monthly. Hot tyres read high, so a check after a motorway run leaves you under-inflated, which lengthens braking distances, wears the shoulders and costs fuel.
Lights and glass
Wipers, washers and all lights must work. A dirty windscreen in low winter sun is genuinely blinding, and spray from a truck can take your vision away for several seconds.
Use headlights, not sidelights, from sunset to sunrise and whenever visibility is seriously reduced. Sidelights make you visible; headlights let you see.
Fog lights are for seriously reduced visibility only, and you must switch them off when it improves — rear fogs in clear conditions dazzle the driver behind and mask your brake lights.
Documents
| Document | Where it lives |
|---|---|
| Motor tax disc | Displayed on the windscreen |
| NCT disc | Displayed on the windscreen |
| Insurance certificate | Produced on request |
| Driving licence | Produced on request |
Minimum legal insurance is third party — it covers injury or damage you cause to others, not your own vehicle.
If you cannot produce a document when asked, you are normally given ten days to produce it at a Garda station of your choice. Failing to do so is itself an offence.
The NCT clock
First test at four years old, then every two years, and annually once the car passes ten. Commercial vehicles are tested annually under the CVRT.
Warning lights
Red means stop as soon as it is safe and investigate. Amber means caution — get it checked. Driving on with a red oil-pressure or temperature light can destroy an engine in minutes.