One in seven (14%) drivers are effectively speeding without even realising it, according to new research from Halfords and the Director of the Centre for Automotive Industry Research at Cardiff University.
The new analysis investigated the impact of worn tyres on stopping distances and showing they pose similar dangers to speeding.
It found that a vehicle travelling at 60mph with worn but still legal limit of 1.6mm has the same stopping distance as a vehicle travelling at 68mph with tyres in ‘good’ condition (4mm), in the same road conditions with analysis conducted based on wet, winter road conditions.
As stopping distance guidelines are based on vehicles having tyres in good condition, and braking distance is a factor in speed limits set on roads, this effectively means that a car travelling at 60mph is speeding by 8mph, and is in fact approaching the national speed limit for a dual carriageway of 70mph.
This is particularly significant as data from Halfords suggests that currently, one in seven cars on UK roads (14% – over 5 million vehicles) are believed to have illegal or dangerously worn tyres, based on the number of vehicles which receive tyre advisories warnings when checked into Halfords garages, showing that their tyres are illegal, or soon will be, and urgently need replacing.
The figures, from Halfords and Professor Peter Wells, are based on tyres at the legal limit of 1.6mm – so still technically road-legal. The seven per cent of all vehicles inspected that already have illegally worn tyres will have even worse stopping distances.
The impact of worn tyres on braking distances was found to significantly increase with speed.
Whilst a vehicle travelling at 30mph with worn tyres is effectively travelling at 34mph, a car travelling at 70mph with worn tyres is effectively moving at 80mph, based on stopping distance.
This means any car with worn tyres on a motorway and doing 70mph is effectively speeding by 10mph.
The impact of tyres on safety cannot be underestimated as they are the only thing that connects a vehicle with the road and the contact patch is about the same as a palm-print. Indeed 60% of dangerous defects (3 in 5) identified at MOT stage are down to tyres.