Two thirds of drivers (68%) do not know that the minimum tread depth for cars and vans is 1.6mm, according to a survey by motoring charity Brake and recovery service Green Flag.
Brake is lobbying the Government to run a campaign to help educate drivers, empower the police to carry out random vehicle safety checks and to raise the minimum tread depth to 3mm.
Motorists are being urged to check tread depth, tyre pressure and look for any other damage such as bulges and tears weekly and before long journeys.
The AA has issued similar advice and specifically warned fleet managers of the risks of breaching health and safety law, should their drivers travel with sub-standard tyres.
If employers fail in their duty of care to their drivers they could face imprisonment or a £20,000 fine, while drivers could rack up three penalty points and a £1,000 fine for each illegal tyre.