Question
What is the outcome of driving on a wet road with bald tyres?
Answer
In the wet, friction and water dispersement between tyres and the road is reduced, lengthening stopping distance and increasing the likelihood of losing vehicle control.
Driving and stopping a car is subject to the laws of physics. The TAC "Wipe Off 5" program is designed to educate drivers into an understanding of stopping distance and the relationship between speed and stopping.
It is accepted that the distance required to stop on a dry asphalt road, from 60 kph with good tyres and brakes, is 45 meters. Travelling just 5 kph faster, results in the vehicle passing through the 45-meter point at 32 kph. TAC television advertising demonstrates this point and urges us to "wipe off 5".
Change the circumstances to a wet road and a vehicle that has not been properly maintained. Worn tyre tread and a less than efficient braking system, adds further distance and a greater likelihood of collision.
In dry weather, with good tyres, the co-efficient of friction between tyres and road is .7. In the wet, it is reduced to .5 (slippery). The resulting increase in stopping distance, from 60 kph, is 53 meters with impact at the 45-meter point being at 32 kph .
A wet road is equal to 5 kph extra speed on good tyres with good brakes. Bad brakes, bad tyres and wet road conditions will result in a far greater stopping distance and increased likelihood of a collision. Additional problems of control also occur when tyres, brakes and suspensions are not in good working order.
As vehicles age and wear and tear to mechanical components becomes a road safety issue, stopping distance in an emergency braking situation increases; add a wet road and poor tyres and we know that the result will be a collision.
Vehicles over the age of 8 years have shown to be more likely to be involved in collisions and result in serious injuries. Worn out tyres represent over 30% of roadworthiness failures in all tests undertaken at the point of transfer of ownership. It should be of great concern to all drivers, and road safety analysts, to know that a large proportion of vehicles are ill equipped to stop in wet conditions.
What is the solution?
Regular maintenance and regular safety checks will dramatically improve tyre condition. Most drivers take little, if any, notice of their tyres and only become aware that tyre tread is dangerously worn and low, when it is pointed out to them.
TACC proposes that a 5-point safety check becomes a pre-requisite before registration renewal each year. Not a full roadworthy test, not a booking to be made on a particular day, but rather, a safety check included at no extra charge during regular maintenance (see 5-Point Safety Card).
It is not possible to control weather, wind, rain and all slippery road surfaces. However, each driver can "wipe off 5" and also drive a vehicle that is kept up to a safe standard.
The "Wipe Off 5" message will be a success if the vehicle is actually capable of stopping safely in all weather conditions.