Safer Driving at Night
As dusk falls, so does our visual ability. Instead of bright, well-defined colors, sharp images and easy tracking of rapid movement, peripheral activity details and hues are indistinct and our ability to pick up rapid movement is greatly impaired.
At night we simply cannot trust our eyes and our vision to the extent we can in daylight - experts reckon at night we only see about a tenth of what we'd pick up in daylight.
What we see and what we don't
Our eyes are actually very good at dealing with a wide range of light intensities - from almost pitch dark through to strong light. But adjusting from one to another takes time. That's why the glare of headlights can pretty well blind you - and even hurt you - if your eyes have become used to the darkness of a quiet country lane.
When it's anything other than good daylight, we're constantly playing catch-up with the information we get from our eyes. That's a scientific fact - inevitably we're all slower to react at night. So as smart drivers we adjust our driving to deal with the restrictions placed on our vision, rather than expecting our eyes to achieve performance levels they're scientifically not capable of achieving.
So how come we see at all? Well, at night we are dependent upon artificial sources of light, and occasionally a contribution from bright moonlight.
The dangers
The first source of danger concerns what we can actually see. Danger can be the result of the restricted vision that occurs when it's dark - after all, 90 per cent of our ability to react depends on what we see. We also become more sensitive to bright lights and other distractions on the road ahead.
With these distractions, it pays to ensure we make a thorough job of planning a journey so we're not trying to read a map or hastily scribbled directions in poor light conditions. It also means we can devote our 100% attention to the driving task, as we know that road signs, vehicles, pedestrians and other hazards are that much harder to see when it's dark.
Driving tired
Fatigue is also a major risk. Not just the straightforward challenge of staying awake at a time when the body naturally wants to slow down and rest, but also the eye fatigue that can come with staring straight ahead for long periods.
One particular effect of fatigue is that it slows reaction times. We may pride ourselves on fast reactions when we're feeling wide awake and fit, but these inevitably slow down when we're tired.
More to the point, we may be in tip-top shape, but are we making enough allowance for other drivers who may have been awake - and at the wheel - for far too long a time?
Alcohol
Beware the effects of alcohol, not just in you but in other road users. It remains a significant factor in fatal road crashes. If you're out and about late on a Friday or Saturday night, be on the lookout for drunken pedestrians who may lurch into your path. And who's to know whether or not the driver behind you has had a drink? Reinforce your safety by thinking for others as well as for yourself.
Be seen
Remember, being seen as just as important as seeing. So don't leave it until well into twilight before you turn your lights on. Someone else's vision may not be quite so good as yours, so why run the risk of having someone run into you because they couldn't see you in time?
Tips for safe night-time driving
* Plan your journey. Think of your own physical limits and build in extra breaks if you have a long night-time drive. Reckon on at least 15 minutes every two hours.
* Check that the indicators, rear lights, brake lights, sidelights, headlights and main beams are all working properly. And have a spare set of bulbs in the car, just in case a bulb fails when you're out and about.
* Get into the habit of regularly cleaning your lights and windows: a regular wipe of your lights is an excellent idea, especially during extended periods of bad weather or in winter when you're likely to pick up mud and dirt. Don't let frost, ice or condensation place further restrictions on visibility.
* Be considerate with use of full beam. Don't use full beam in town, make sure you dip your headlights when you're behind someone else or when another vehicles is approaching from the other way.
* Have a dazzle policy - if you find you're being blinded by someone else's full beam and it's safe to do so, then slow down or even stop until they've gone by. Don't meet their full beam with full beam of your own. Don't match their mistake with similar actions of your own.
* Keep alert. It really pays to keep a good lookout for other road users. As we've seen, it's much harder to see them at night - even if they are wearing a fluorescent jacket. Pedestrians on country lanes without pavements, cyclists, revellers coming out of pubs or clubs at closing time... you'll often not see someone until you're really close to them.
* You need to increase gaps between yourself and the vehicle in front. Decrease your speed, increase the time and space you've got to stop safely. You won't be able to see hazards as early as you can in daylight, so make sure you compensate by building in extra time and space - and they both come from reducing your speed.
* Remember that at night the likelihood of someone else doing something to endanger you is of course greatly increased. It's usually at night that people drink, take drugs - or try and break into your car... and obviously pay special attention if you're on the road when the pubs or clubs are closing.
David Williams was awarded the MBE in 1998 for services to Road Safety. He is Chief Executive of GEM Motoring Assist, who sell the best breakdown cover covering both car and caravan recovery.