Car owners face a tougher National Car Test (NCT) from Monday for a range of faults including misaligned headlights and improper number plates.
Until now a number of defects have been classified as a "fail advisory", which was simply a warning. However, from next week car owners will be refused a test certificate if the faults are not repaired.
The move is the final step in the phased implementation of the NCT since testing began almost four years ago.
Figures for this year show the failure rate for the NCT is running at 46 per cent, and this figure is expected to increase when the new measures are introduced.
Misaligned headlights have been among the most common faults detected at test centres, which have only incurred a caution until now.
From Monday, a car owner whose vehicle fails the test for faults which previously carried a warning will have to have their car repaired and retested before receiving a NCT certificate. A full test costs €48.40, while retests cost €27.20.
Announcing the changes yesterday, the Minister of State for Transport, Dr James McDaid, said the move would help improve road safety.
"Defective headlights are a serious road safety issue which must be confronted once and for all. Persons driving vehicles with misaligned headlights are not just a danger to themselves, but are putting at risk the safety of all other road users."
In advance of the changes, letters have been issued to car owners which include a list of the new reasons for refusal of a test certificate.
Overall, failure rates for the NCT have been falling since it was introduced. The pass rate for full tests in 2000 was 46 per cent, compared to 54 per cent so far this year.
Tests are conducted on cars more than four years old.
In a separate development, motorists will have to know how to fix their cars as part of an overhaul of the driving test.
As part of the driver theory test, learner drivers will be questioned on the mechanical aspects of their car.
Failure to correctly answer three mechanical questions, such as how to lift the bonnet, or explain how oil, windscreen washer-fluid or engine coolant is checked, will record a fault in their test.
A spokesman for the Minister for Transport, Mr Brennan, said driving testers were being trained in preparation for the new measures, which will be introduced in the coming weeks.
"It's not about making drivers into mechanics. It's just ensuring that someone has basic knowledge of a car, and if it breaks down they would at least be capable of assessing the damage," the government spokesman said.
Vehicles with the following faults will automatically be refused a NCT certificate from Monday:
- Misaligned headlights
- Registration plates not conforming to legal requirements
- Worn break pedals
- Defective horns
- Faulty windscreen wipers
- Missing or damaged rear-view mirrors
- Front and rear wheel misalignment
- Imbalance in shock absorbers
- Rear-view mirror missing or damaged
- Defective handbrake,
- faulty doors,locks, anti-theft devices
- Defective side lamps
- Misaligned auxiliary lamps
* For further information, log onto www.nct.ie