Driving at Night
Staying safe when your vision is considerably restricted
There’s no doubt that the human eye performs best in daylight. Colours are generally well defined, images are at their sharpest and we're good at picking up rapid movement and peripheral activity.
Head for dusk and eyesight quality diminishes. We can no longer trust our vision as we might do in full daylight. You'll no doubt have had a few experiences where you thought you saw something and it actually turned out not to be that at all.
Next let us think of night time, where all those details we understood so well during the day are much less defined. Our ability to pick up movement is still there but it's slower. Because there's less detail then we're not so good at judging movement - and experts reckon we see only about a tenth of what we would pick up in broad daylight.
What we see and what we don't
Our eyes are actually very good at dealing with a wide range of light - 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 seeing and observing. And 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 tasks they're scientifically not capable of achieving.
The first source of danger concerns what we can actually see. It's a scientific fact that at night we simply cannot trust our eyes and our vision to the extent we can in daylight.
Danger can come from the restricted vision that occurs when it's dark. After all, 90 per cent of our ability to react depends on what we see. So it stands to reason that if we see a lot less at night, then we are automatically in a more dangerous environment.
So how come we see at all? Well, at night we are dependent upon artificial sources of light. We also become more sensitive to bright lights and other distractions on the road ahead. That's why 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.
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.
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 look-out 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.
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!
Safe night-time driving advice
• 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. As we've said before, you need to make an active choice not to 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.