Tyre checks on company cars throughout the country as part of a new safety programme revealed that 10% of tyre tread depths were below or close to the legal limit when checks were carried out.
As well as risking accidents, employers leave themselves open to legal action if they are shown to have failed in their duty of care to keep staff safe on the road while travelling on business.
The fleet tyre survey, carried out by Kwik-Fit Mobile, coincided with a recent spot check on motorists by police in Essex, who found that 13% of motorists had defective tyres.
Although drivers may dismiss the dangers involved in defective tyres, research has proved that at 70mph, the stopping distance of a car fitted with a new tyre is about 100 metres, while one with 3mm of tread is 150 metres.
At the legal minimum of 1.6mm, the stopping distance doubles to 200 metres, and extends even further to 250 metres when only 1mm of tread is left.
With the current maximum fine for having illegal tyres standing at £2,500 per tyre and three points on a driving licence, Kwik-Fit Fleet director Simon English said employers had to rethink their attitudes to tyre safety.
'Ensuring tyres meet legal requirements is a vital part of any corporate risk strategy, but human safety far outweighs the legal issues,' he said.
Kwik-Fit Mobile estimates that on average when it first checks a fleet's tyres as part of its Safety Check service, 10% of tyres are potentially dangerous.
Research programmes carried out by a wide range of manufacturers and tyre providers have hammered home to fleets that poorly maintained tyres can increase fuel consumption, lead to higher wear and tear costs and jeopardise driver and passenger safety.