Clean Windscreen Reduces Braking Distances

Keeping your windscreen spotlessly clean could cut one second off your braking response in an emergency – enough to prevent a smash from occuring.

The finding was made by the University of Michigan Transportation Research Institute testing a special type of glass treatment developed by specialist cleansing products maker Rain-X that helps to stop dirt and water sticking to windscreens.

It may appear obvious that a dirty windscreen can prevent the driver from seeing an emergency situation quickly enough to respond, but this is the first time the theory has been tested and quantified.

It’s called the 1-second advantage.

In the so-called “Visual Acuity” tests, the Institute calculated that the driver of a car with a smeared windscreen travelling at 100km/h would react one second later than the driver looking through Rain-X treated, clean glass. The difference travelled during the lost reaction time was 27metres.

For a car travelling at 50km/h, the vehicle with the impaired windscreen visibility travelled a further 13.5metres.

The Institute says that with a clear windscreen, the average braking response time time was 0.5 seconds, against 1.5 seconds for the driver trying to peer through a dirty windscreen. Actual response times could vary according to the time of day, condition of the vehicle and the road and weather conditions.

The tests validated the effectiveness of the hydrophobic glass treatment developed by Rain-X, which is now available through service stations and leading automotive accessory outlets in New Zealand.

According to its distributor, Griffiths Equipment, Rain-X Origninal windscreen glass treatment is the leader in its market in the US.

To work effectively it has to be applied to a clean windscreen, which can be done with a cloth. The hydrophobic molecules contained within the solution bond to the glass surface, forming an invisible shield that causes water to bead and roll off – providing much improved visibility in wet weather conditions (it’s possible to see through the windscreen in the rain without using the wipers).

Similarly, dirt cannot get a grip on the screen and falls away. Sleet and snow is dealt with in the same way. It acts just like wax and polish on the paintwork, except that it is specially formulated for glass, whereas waxes and polishes leave streaks and smears on windows.

The makers say Rain-X Original prevents wipers from creating streaks on the glass and provides a clean and smear-free view of the road ahead.

For best results it should be applied once a week, after every car wash, and the cloth should also be used to wipe the blade of the wipers to help smooth their action across the screen.

Rain-X can be used on all exterior glass surfaces around the vehicle, including the mirrors. There’s also a Rain-X Washer Fluid additive for washer bottles that helps to apply a little of the repellent treatment each time it is used – but does not fully replace the need to regularly treat the windscreen.

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