Bald or defective tyres were partly to blame for road accidents in which 71 people died over five years, research has revealed.
Analysis of forensic crash reports from 2008 to 2012 showed vehicle defaults such as poor brakes, steering, suspension or tyres played some role in one in every eight collisions.
The Road Safety Authority (RSA) said 111 people were killed and another 30 were seriously injured in these accidents.
New laws are being drafted to hit motorists with penalty points if their vehicle is being driven on bald or defective tyres, acting Transport Minister Paschal Donohoe said.
“None of us can predict what will happen when we use the roads – we may encounter other drivers behaving poorly, or weather conditions could be particularly bad,” he said.
“But we can take personal responsibility for ensuring our vehicle is properly maintained so that we can rely on our tyres responding to the conditions as they should or our brakes working when they need to.”
The research for the RSA examined forensic details of 867 fatal collisions over the five year period to identify the cause of the collision.
Vehicle factors, such as defective tyres, brakes, steering or suspension, were found to have contributed to 101 of these fatal collisions, along with other behaviours such as speeding, alcohol or drug use.
It found the condition of tyres accounted for almost two thirds of collisions and almost three quarters of single vehicle accidents.
More than half (51.5%) of the tyres on the 66 vehicles with defective tyres were excessively or dangerously worn and 10.6% were under-inflated, some dangerously low.
Some 6% showed a combination of excessively worn, being under-inflated, the wrong size or fitted wrongly.
The RSA analysis found 18 people were killed and six were seriously injured in a crash where a vehicle had defective brakes.
Elsewhere, young drivers aged 17-24 were involved in almost half the fatal collisions which involving vehicles with defective, worn or over or under-inflated tyres.
The RSA said Donegal had the biggest issue with tyre defects with 18% of motorists involved in accidents driving vehicles with defective tyres followed by Cork, Kerry and Wexford on 9% each.
The report on the causes of crashes also noted that losing control on a bend on a regional road and on a road surface that was dry at the time were typical scenarios.
The RSA urged drivers to have their tyres checked in a garage about once a month.
Moyagh Murdock, the agency’s chief executive, said: “This report shows that tyres are the parts of your car that are most likely to put you at risk of a fatal collision if they’re not roadworthy.
“Don’t assume you can tell if there’s a problem just by looking at them – you can’t.”
Garda Chief Superintendent Aidan Reid said: “Tyres are the only part of your vehicle that keep you in contact with the road so it is critical that they are in roadworthy condition at all times.
“Your safety, along with the safety of your passengers and other road users, could depend directly on the condition of your vehicle’s tyres. If your tyres are worn, under or over-inflated, the wrong size, or damaged in any way, they won’t respond properly in an emergency, or poor weather conditions.”
The data was released to coincide with a new ad campaign on the dangers of driving with defective tyres which will run on television, radio, cinema and online.