Have you ever thought ‘Am I going blind? Where did they come from?’ or heard (or used the phrase), ‘Sorry mate, I didn’t see you’. Drivers up and down the country have probably thought this at least once, but is it careless driving or a genuine mistake?
A report by John Sullivan of the RAF has the answer, and the repercussions of this will change the way your driver or cycle. (This is just a very brief summary but the full report can be found here1211 Road Survival Guide Final – fighter pilot.)
John Sullivan, an Royal Air Force pilot with over 4,000 flight hours in his career, believes lessons used by fighter pilots can help make us all better road users. Fighter pilots have to cope with speeds of over 1000 mph so being aware of any limitations is important in ensuring everyone is kept safe.
So what’s the truth of the matter? Well, simply put, your eyes are failing you! For small but significant periods of time you are completely incapable of seeing anything at all! The good news is that if you know it you can do something about it.
Why do our eyes fail us?
From hundreds of thousands of years of evolution our eyes, and the way that our brain processes the images that they receive, are very well suited to creeping up on unsuspecting antelopes and spotting threats such as sabre-toothed tigers.
These threats are largely gone and they’ve been replaced by vehicles travelling towards us at high speeds. This, we’ve not yet adapted to deal with.
Why? (here’s the science bit!)
Light enters our eyes and falls upon the retina. It is then converted into electrical impulses, that the brain perceives as images. Only a small part of your retina, the centre bit called the fovea, can generate a high-resolution image. This is why we need to look directly at something, to see detail.
The rest of the retina lacks detail but it contributes by adding the peripheral vision. However, a mere 20 degrees away from your sight-line, your visual acuity is about 1/10th of what it is at the centre.
Try this scary test to see quite how much detail you lose in your peripheral vision
- Stand 10 metres away from a car.
- Move your eyes and look just one car’s width to the right or left of that car.
- Without moving where you eyes are now looking, try to read the number plate of the car.
- Try the test again from 5m.
The test shows you quite how little detail you are able to truly capture from the side of your eyes.
That’s not to say that we cannot see something in our peripheral vision – of course we can. As you approach a roundabout, you are likely to see a huge lorry bearing down upon you, even out of the corner of your eye – obviously, the bigger the object, the more likely we are to see it. But would you see a motorbike, or a cyclist?
To have a good chance of seeing an object on a collision course, we need to move our eyes, and probably head, to bring the object into the centre of our vision – so that we can use our high-resolution vision of our fovea to resolve the detail.
Another test to try
- Look in a mirror.
- Look repeatedly from your right eye to your left eye.
- Can you see your eyes moving? You can’t.
- Repeat the test with a friend and watch them. You will see their eyes moving quite markedly.
You can’t see your own eyes move because your brain shuts down the image for the instant that your eyes are moving. This is called Saccadic masking.
In the past, this served us well. It meant we could creep up on antelopes without our brain being overloaded by unnecessary detail and a lot of useless, blurred images.
However, what happens when this system is put to use in a modern-day situation, such as a traffic junction?
When you move your head and eyes to scan a scene, your eyes are incapable of moving smoothly across it and seeing everything. Instead, you see in the image in a series of very quick jumps (called saccades) with very short pauses (called fixations) and it is only during the pauses that an image is processed.
Your brain fills in the gaps with a combination of peripheral vision and an assumption that what is in the gaps must be the same as what you see during the pauses.
This might sound crazy, but your brain actually blocks the image that is being received while your eyes are moving. This is why you do not see the sort of blurred image, that you see when you look sideways out of a train window.
The only exception to this, is if you are tracking a moving object.
But it’s summer. Surely I can see road users at this time of year?
Not necessary! Even on the sunniest day elements like glare or shade can hinder your vision. Have a look at the following pictures below to see what I mean.
Can you see the moped driver in the picture above? (Hint: the middle tail light)
And how about the moped in this photo (above)?
The close up here shows the moped rider, who, even with their headlights on is difficult to see!
So what can we do?
- Slow down on the approach of a roundabout or junction. Even if the road seems empty. Changing speed will allow you to see vehicles that would otherwise be invisible to you.
- A glance is never enough. You need to be as methodical and deliberate as a fighter pilot would be. Focus on at least 3 different spots along the road to the right and left. Search close, middle-distance and far. With practise, this can be accomplished quickly, and each pause is only for a fraction of a second. Fighter pilots call this a “lookout scan” and it is vital to their survival.
- Always look right and left at least twice. This doubles your chance of seeing a vehicle.
- Make a point of looking next to the windscreen pillars. Better still, lean forward slightly as you look right and left so that you are looking around the door pillars. Be aware that the pillar nearest to you blocks more of your vision. Fighter pilots say ‘Move your head – or you’re dead’.
- Clear your flight path! When changing lanes, check your mirrors and as a last check, look directly at the spot which are going to manoeuvre.
- Drive with your lights on. Bright vehicles or clothing is always easier to spot than dark colours that don’t contrast with a scene.
- It is especially difficult to spot bicycles, motorbikes and pedestrians during low sun conditions as contrast is reduced.
- Keep your windscreen clean – seeing other vehicles is enough of a challenge without a dirty windscreen. You never see a fighter jet with a dirty canopy.
- Finally, don’t be a clown – if you are looking at your mobile telephone then you are incapable of seeing much else. Not only are you probably looking down into your lap, but your eyes are focused at less than one metre and every object at distance will be out of focus. Even when you look up and out, it takes a fraction of a second for your eyes to adjust – this is time you may not have.
Cyclists and motorcyclists:
- Recognise the risk of being in a saccade. High contrast clothing and lights help. In particular, flashing LED’s (front and rear) are especially effective for cyclists as they create contrast and the on-off flashing attracts the peripheral vision in the same manner that movement does. There’s nothing wrong with leaving these on during the day.
- The relatively slower speed of bicycles means that they will be closer to a point of collision if a vehicle begins to pull into their path. Turn this to advantage – when passing junctions, look at the head of the driver that is approaching or has stopped. The head of the driver will naturally stop and centre upon you if you have been seen. If the driver’s head sweeps through you without pausing, then the chances are that you are in a saccade – you must assume that you have not been seen and expect the driver to pull out!
- Recognise that with a low sun, a dirty windscreen or one with rain beating against it drivers are likely to have less of a chance of seeing you.
- Cycle instructors have been saying it for years: Ride in a position further out from the kerb as a driver is more likely to be looking in this location.
Much of the information in this article has been taken from the original article (http://www.londoncyclist.co.uk/raf-pilot-teach-cyclists/) written by Andreas for London Cyclist, in November 2012.