Tyres with tread depths below the legal limit are now the main cause of NCT failures, with almost 33,000 cars being put off the road - at least temporarily - last year.

Almost 33,000, or 2.6 per cent of the total of over a million cars tested, failed the NCT last year. Most of them had tyre tread depths at or below 1.6 mm - the depth at which the tyres are deemed to provide little or no grip. When tyres have an 8 mm tread depth they are deemed to be at their most effective.

More faults that can cause accidents are now covered by the NCT test.

An EU directive introduced last year means that a greater number of defects are covered by the "dangerous" categorisation. These now cover more tyre and brake issues which can contribute to a crash or make one more difficult to avoid one. 

The main criteria applied after NCT testing are now:

  • Pass: The vehicle has passed the NCT
  • Minor Result: This means that a vehicle has passed the NCT with minor faults recorded
  • Major Result: Vehicle has failed the NCT and must return to the centre for re-inspection within 30 days.
  • Dangerous Result: Vehicle has failed the NCT due to dangerous defects that constitute a direct or immediate risk to Road Safety such that the vehicle should not be used on the road under any circumstances.

Owners have a 30 day period to get the appropriate repairs carried out or face a full re-test. 

If a car has been given a dangerous designation, the owner no longer has a valid NCT certificate. For someone found driving without a certificate - Gardai can check a database to establish whether a car has failed its test - the potential court penalties are:

  • A fine of up to €2,500 and or term of imprisonment of up to 3 months: 
  • Five penalty points
  • With a first conviction a disqualification from driving is not automatic, but can be imposed depending on the circumstances:
  • With a second conviction within 3 years of the first, the driver will automatically be disqualified from driving for at least 12 months.