More than half the vehicles which failed the mandatory car test on its first day had faulty brakes, according the National Car Testing Service (NCTS).
The NCTS's general manager, Mr Richard Horque, said it was surprising that such a high number of vehicles were rejected for so fundamental a problem which leads to increased accidents.
Almost four in every five of the 300 cars tested on the initial day of the State-wide compulsory car inspection failed to get a certificate of roadworthiness.
Some 55 per cent of the rejected vehicles, aged nine years and older, failed due to faulty brakes. A further third failed due to substandard emissions.
Mr Horque said these findings indicated that car services were either not being carried out at all, or were not effective.
"It's fundamental that a car's brakes work and work to a safe limit. If they do not, you increase your likelihood of a collision and increase the impact of it if you are going too fast," he said.
While mechanics and motor factor companies prepare to cash-in as owners of rejected cars remedy their faults, Mr Horque reassured customers that most failed vehicles would only need minor repairs. Of the 79 per cent of cars which failed the test, 51 per cent had only one defect, while 27 per cent had two defects. Below are answers to some common questions about the test:
When will my car be called in for a test?
The compulsory tests are being phased in over two years, starting with cars aged nine and over. All cars first registered before 1992 will be tested this year, with cars first registered between 1992 and 1996 tested in 2001, and all four-year-old cars tested from 2002 onwards.
Eventually, all cars aged four or over will be tested every two years.
How can I prepare for the test?
The NCTS recommends that cars have a pre-test service to avoid disappointment over something which could be easily fixed.
What will be examined during the test?
The main elements examined in the three-stage test are: brakes, exhaust emission, wheels and tyres, lights, steering and suspension, chassis and underbody, electrical systems, glass and mirrors, transmission, interior and fuel system.
How much does it cost?
The test costs £35 per car, including VAT. A retest is £19.80, but retesting on a minor flaw which can be done by visual inspection is free. There is no subsidy for disabled drivers or pensioners.
What happens if my car passes the test?
A certificate of roadworthiness valid for two years will be issued on the day of the test, along with a disc which must be displayed on car windscreens.
What happens if my car fails the test?
A retest will be carried out within 28 days. The test failure notices state the reasons for failure and drivers are advised to bring their cars to a mechanic to have the problem fixed before attending the retest.
What happens if my car fails the retest?
It has to undergo another full test. The testing and retesting may continue until the tax disc period expires. Cars which have been tested and do not have NCTS certificates will not be issued with new tax discs.
Owners of cars which are declared "dangerous" by testers will be offered the telephone number of a tow-away service. The NCTS has no power to impound dangerous cars.
How will car testing be enforced?
The Garda and not the NCTS will enforce the law against car owners whose vehicles fail the test. Those detected by gardai will be liable to prosecution, and a possible £350 fine.
From April 1st, cars must display an NCT disc on their windscreens.
Are any cars exempt from the NCT?
All cars taxed as vintage and cars permanently based on islands not connected to a mainland road will not have to be tested.
More information is available from the NCTS website at www.ncts.ie