In long spells of dryness substantial deposits of oil, rubber and waste fuel accumulate on road surfaces. When the roads are dry these deposits aren’t too much of a problem but introducing moisture into mix changes the situation dramatically.
Oil/fuel and water do not mix, causing a tactile film to float on the surface of the moisture which reduces the ability of tyres to gain traction on the road. This, in turn affects directional control and braking.
The first five minutes of a downpour are the most crucial, creating conditions that are different to those encountered with just standing water. The drains cannot begin to clear the oil and water mix until there is sufficient volume to reach the drains and cause a continual flow.
While this is happening vehicle traction is greatly reduced. Motorcyclists are vulnerable to the reduced visibility through ‘dirty’ spray, manhole covers and any painted lines on the road which become more slippery. For drivers, windscreens suffer with a milky-like residue thrown up from vehicles in front which could cause the driver to drive blind until it clears.
Howard Redwood head of road safety for Diamond Advanced Motorists expressed the need for caution: “Before going out in your car, check that your windscreen washer fluid is topped up and wiper blades are in good condition. Ensure that your tyres have enough tread and at the correct pressure and always leave a substantial stopping distance.
“These three simple things should help you deal with whatever the unpredictable British weather can throw at you, all year round.”