§ Mr. Iain Millsasked the Secretary of Transport (1) if he will estimate the average percentage decrease in usable tyre life as a result of requiring (a) the existing minimum tread depth of 1 mm to be a continuous band over three-quarters of the tread width and round the full circumference plus visibility of the remaining 25 per cent. of tread, (b) 1 mm tread depth over 100 per cent. of the tread and (c) an overall tread depth of 1.6 mm;
(2) on what criteria he formed his view that a change to a minimum of 1 mm tyre tread depth across the full 187W width of a tyre would cost motorists and the transport industry a significant amount; and whether he has made an assessment of potential accident savings.
§ Mrs. ChalkerThe information available to the Department on usable tyre life, as compared with existing requirements, is as follows:
- (a) Few tyres are affected. Precise percentage estimates are not available.
- (b) About 30 per cent. of tyres in use would be affected, with their lives reduced by around 12 per cent.
- (c) Most tyres would be affected, with their lives reduced by around 14 per cent.
The cost of (b) is estimated at £22 million per year. The evidence on adhesion in the wet of tyres under (a) and (b) suggests that there would be no significant difference in the numbers of accidents.