The number of people driving 'death trap' cars has shot up dramatically.
The cars are being detected when taken to an NCT centre. Up to the end of November, NCT staff found 6,499 'fail/dangerous' vehicles.
That is 1,000 more than in all of 2015 when 5,432 were discovered, and an even bigger increase on the 4,800 for 2014.
Such is the level of risk around these cars that when one is discovered, NCT staff immediately advise the owner to have it towed, rather than driven, away from the test centre.
The 'fail/dangerous' vehicles also have a special sticker put on their windscreens to indicate their 'perilous' status. And an NCT official reads out a formal statement to each owner detailing why and how their car is dangerous and un-roadworthy.
Many owners are shocked and decide to have the car towed away. However, a small number have been known to ignore warnings and drive off.
Car testing is overseen by the Road Safety Authority. A spokesman told the Irish Independent: "The vehicles were considered to constitute a direct and immediate risk to road safety and should not be used on the road under any circumstances."
He said it is an offence to drive such a vehicle.
"When the NCT was first introduced, more than 4pc of vehicles failed with a dangerous defect.
"Since then there has been a phenomenal increase in the number, and age, of cars on our roads. In today's terms, that would be 60,000 dangerously defective vehicles on our roads if we didn't have the NCT."
The increase in detections is attributable to higher volumes of older cars being tested more regularly.
And many people are holding onto cars for longer because they can't afford to change up.
Elements making cars 'fail dangerous' include:
Bodywork so badly corroded the car is structurally dangerous;
Doors so out of alignment they cannot be closed properly;
Worn or badly frayed fuel hoses that could start a fire if petrol dripped onto hot areas of the engine;
Major leaks of brake fluid due to flawed lines or hoses;
Bulging, unevenly worn or bald tyres.
Traffic management plans coming into force by the end of 2017, when Luas Cross City begins operations, will effectively act as a 'congestion charge' as it will be impossible to drive in certain streets.