Driving under poor conditions is more than just icy or wet roads. Some of the worst situations include dusk and night driving; rain, fog, snowstorms, and drifting snow; sunshine and shadows; and driving towards the sun. These problems are discussed separately in the following sections.

Dusk

During this period of half-light, the cone central vision is not as efficient as in daylight, but your eyes are not yet prepared for night vision either. Professional drivers try not to drive during this period if they can help it. Whenever practical, they will stop and take a meal or a rest to help their eyes adapt to the dark. If you must drive, it is imperative that you reduce speed and be particularly alert.

Night Driving

At night the eye sees persons or objects by contrast – light colored clothing or objects stand out against a darker background; or by outlining – dark clothing or objects are silhouetted against a lighter background. People, animals, and objects are more or less visible depending on the amount of light they reflect to the observer. It is well known that light colored clothing or objects reflect more that dark colored objects, and so will be seen from a greater distance. But a driver cannot count on other people or animals to make themselves more visible. A driver never knows when his headlights will reveal – too late – a darkly dressed pedestrian or a car parked without lights.

When driving at night, your reference point must be a little higher than the meeting point of the headlight and the pavement in the center of your lane.

Peripheral vision suffers less than central vision at night. It is very important that you train yourself to use your peripheral vision extensively when driving in daylight so that it becomes a firmly set habit that you simply carry on at night. Otherwise, you may use only your central vision in the narrow cone of light. This concentration of the eyes and attention reduces the efficiency of the peripheral vision. The eyes would not move as they should, and, because of that lack of movement, eye fatigue may set in. As we discussed before, double or one eyed vision may result.

Preparing Your Eyes for Night Vision

Your vision takes time to become efficient at night. It has been determined that it takes at least 30 minutes to get to 80 per cent of the efficiency, and at least one hour to reach 100 per cent. You can lose a good percentage of this adaptation to the dark by just looking at streetlights or the headlights of another car. When you drive at night, therefore, always keep the following points in mind:

1. When meeting a car, look to the right of the road, higher than the point where the light and pavement meet, using your peripheral vision to detect possible motion

2. Never drive at night when tired. Stop and rest.

3. Remember that distance judgment is much more difficult at night, because you may tend to overestimate the distance between you and other cars, and under estimate your speed. You must be especially alert when judging distances to red lights – this color presents special difficulties, so allow plenty of space when following another car, and more space to stop than would seem necessary at a red traffic light.