Heavy Rain and Road Spray

Poor drivers will tell you that headlights are fitted to cars so that you can see where you are going in the dark. Wise drivers, on the other hand, will tell you that headlights let you see and be seen.


If you are traveling at 40mph, your car is covering almost sixty feet per second but how long did it take you to spot the two cars without lights in this photograph? (Yes, there are two. One is coming out of a side road.) Photo: Ian Britton, freefoto.com

Reduced visibility is one of the two main challenges to drivers during rainfall or heavy surface-spray, and the other is a reduction in grip between the tires and the road surface, but we will come to that below.


A rule for wise drivers: “Windshield wipers on means low-beam headlights on, too!”
Unlike the third car, here, let other drivers and pedestrians see you in good time.
Photo: Ian Britton, freefoto.com

The reason that you must never rely on “Daytime Running Lights” in poor light or bad visibility is, of course, that they only operate at the front of the vehicle. If you are driving in heavy surface-spray, or in fog, heavily falling snow or half-light then your rear lights are vital to your safety. If you cannot be seen clearly from behind then one day it is inevitable that your car will be hit. And if it just happens to be an 18-wheeler coming up behind…

freefoto-heavyroadspray01--21_85_56_webIn the sections on fog and heavy falling snow, high intensity rear fog lights will be mentioned. In bad weather they are excellent for extra protection.

The other potential hazard, in bad weather conditions, is the reduction of traction between your tires and the road surface.

Always allow for the fact that it can take twice as far to stop your car when the road is wet. For following another vehicle on a dry road, the rule says “only a fool breaks the two second rule,” but when the road is wet it is important to allow at least a four-second gap between vehicles, rather than two.