by Paul Murphy
If you think a newly acquired NCT cert means your car is roadworthy, you may be wrong. The NCT, a test that is laid down in law, has a number of flaws that the public does not appear to be aware of.
Take the NCT suspension test which is effectively a test of your shock absorbers. We need shock absorbers to keep our tyres in contact with the road. “If the tyre is failing to maintain [contact] ... the car won’t break properly. It won’t corner properly. It won’t accelerate properly.. It can be as bad as driving on ice,” vehicle dynamics engineer Matt Taylor told the Investigations Unit.
Experts we spoke to say it is possible for the NCT to pass a car where all of its shock absorbers are defective. The NCT checks shock absorbers as part of the suspension test in two ways. First there is a visual check for oil leaks. Second, the NCT tests vehicles on a machine to check their balance. Car wheels are moved up and down and the movement of the vehicle suspension is recorded with a measurement called Mahameters, which is essentially the same as millimeters. If the wheels are in relative balance (within a 30% differential between right and left) they will pass. But if they are equally defective and there is no imbalance the shock absorbers will pass the balance test. They may also pass the visual test because experts say oil leaks are not always visible on defective shock absorbers.
This means that motorists can leave an NCT centre with a roadworthiness certificate saying that their suspension has passed even though it may be in what experts describe as “a dangerous condition”.
Vehicle experts have told the Investigations Unit that if a car registers a NCT machine reading above 80 Mahameters it should raise a red flag because it suggests the shock absorbers need to be replaced. Yet cars pass the NCT with readings well in excess of that. According to test results seen by the investigations unit, one car passed with shocks showing readings of 159 Mahameters on one side and 178 on another. Experts we spoke to say readings that high would indicate this car was unstable but it passed because the wheels were in relative balance.
Corkwoman Paula Murphy lost her daughter, Amanda O’Flaherty, in 2012 in a car accident. We will never know what caused the accident. The inquest into Amanda’s death heard evidence from a Garda vehicle inspector who examined the car after the accident. He told the inquest that the car was “not in a roadworthy condition prior to the collision” because the two rear shock absorbers “were leaking an excessive amount of oil… thus making the vehicle very unstable before and during cornering.” The accident happened seven months after Amanda’s car was NCTed. She clocked up nearly 1300 miles between the test and the accident. The readings at the time of her test were 94 Mahameters on one rear wheel and 96 on the other.
When presented with those readings, Paul Young from DCU’s Department of Mechanical Engineering said, “I would definitely be replacing those shock absorbers straight away. There wouldn’t be any delay in that for my safety driving the car and for the safety of other road users.”
Matt Taylor echoed this view. “I would change the shock absorbers,” he said “I wouldn’t drive it because no amount of skill can compensate for the fact the wheels aren’t touching the floor.”
The Road Safety Authority, however rejected the idea that readings on Amanda O’Flaherty’s car were abnormally high. In a statement a spokesperson said at the time of the test there was no “evidence of fluid leakage presented” and “The RSA is of the view that the car was not defective at the time of the NCT and that readings of 94Mm/96Mm are not sufficient as a basis to establish the roadworthiness of a car. It is our experience that these readings or similar readings are not the cut-off point to deem a shock absorber defective," the organisation said in an email.
In an interview with RTÉ, the RSA Chief Executive, Moyagh Murdock, said that the Irish NCT is “highly sophisticated and probably the most sophisticated in the member states involved in the road safety strategy.” She also points out that there is no consensus in Europe on how best to test suspension systems and Ireland is one of only five EU states that do a balance test as well as a visual check on shock absorbers.
There are also considerable inconsistencies between some of the 47 test centres around Ireland, where pass rates can differ dramatically from centre to centre. Since 2011, there has been a gap of around 19% to 30% between the centres with the highest and the lowest pass rates. In 2011, 70% of vehicles passed at the Cahirciveen NCT centre while in Clifden it was 40%. In 2012 67% passed at Cahirciveen but only 39% in Carrick-on-Shannon. In 2013 55% passed at Tralee but only 36% at Clifden and in 2014 58% passed at the Kilkenny NCT centre but only 35% at Clifden.
In the North where cars are tested at 15 centres, the difference between the pass rates is far smaller. In the most recent years for which figures are available the difference was just 7%. In 2014, Belfast had the highest pass rate at 85% and Cookstown the lowest at 78%. In 2013 the highest pass rate was 84% in Belfast and the lowest 77% in Cookstown. Again in 2012 the difference between the highest and lowest pass rates in the North was just 7%, compared to as much as 30% in the 26 counties.
