Tyres on cars, light vans and trailers must have a continuous tread depth of at least 1.6 mm. How much of the tyre must have this depth of tread? Tyres on cars, light vans and trailers must have a continuous tread depth of at least 1.6 mm. How much of the tyre must have this depth of tread?

• Possible answers:

   
• A. The central three-quarters of the width of the tyre
• B. The outer edges of the tyre
• C. The whole width of the tyre
• D. The central half of the width of the tyre