“Sorry mate, I didn’t see you”. Is a catchphrase used by drivers up and down the country. Is this a driver being careless and dangerous or did the driver genuinely not see you?
According to a report by John Sullivan of the RAF, the answer may have important repercussions for the way we train drivers and how as cyclists we stay safe on the roads.
John Sullivan is a Royal Air Force pilot with over 4,000 flight hours in his career, and a keen cyclist. He is a crash investigator and has contributed to multiple reports. Fighter pilots have to cope with speeds of over 1000 mph. Any crashes are closely analysed to extract lessons that can be of use.
Note: You can now download the original article by John Sullivan which includes further insights: Dropbox link.
Our eyes were not designed for driving
We are the result of 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These threats are largely gone and they’ve been replaced by vehicles travelling towards us at high speeds.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?
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 sightline, 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 and 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 would be hard pressed not 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.
Here’s when things get really interesting
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.
Another test to try
If you are not convinced, try this test.
- 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?
Why we miss motorbikes and bicycles
At a traffic junction all but the worst of drivers will look in both directions to check for oncoming traffic. However, it is entirely possible for our eyes to “jump over” an oncoming bicycle or motorbike.
The smaller the vehicle, the greater the chance it will fall within a saccade.
This isn’t really a case of a careless driver, it’s more of a human incapacity to see anything during a saccade. Hence the reason for so many “Sorry mate, I didn’t see you” excuses.
The faster you move your head, the larger the jumps and the shorter the pauses. Therefore, you’ve got more of a chance of missing a vehicle.
We are effectively seeing through solid objects, with our brain filling in the image.
Additionally, we tend to avoid the edges of the windscreen. The door pillars on a car therefore create an even wider blindspot. This is called windscreen zoning.
The danger of playing music
Our ears help us build up a picture of our surroundings. However, inside our cars or with music playing, our brain is denied another useful cue. Additionally, bicycles are almost completely silent, so won’t be heard by car drivers.
How accidents happen
Let’s say you are driving along. You approach a junction and you notice a lack of traffic. You look left and right and proceed forward. Suddenly you hear the blast of a horn, as a motorbike flashes in front of you, narrowly avoiding an accident.
What just happened?
On your approach, you couldn’t see there was another vehicle on a perfect collision course. With a lack of relative movement for your peripheral vision to detect and the vehicle being potentially hidden by being near the door pillar, you miss it entirely.
Lulled into a false sense of security you looked quickly right and left, to avoid holding up the traffic behind you, and your eyes jumped cleanly over the approaching vehicle, especially as it was still close to the door pillar in the windscreen. The rest of the road was empty, and this was the scene that your brain used to fill in the gaps! Scary, huh?
You were not being inattentive – but you were being ineffective.
Additionally, if you didn’t expect there to be a cyclist your brain is more likely to automatically jump to the conclusion that the road is empty.
Now that you’ve been warned. What can you do?
Forewarned is forearmed, so here’s what we can do.
Drivers:
- 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 then 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. (Especially if they are rechargeable)
- 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.
- Take a cycle training course – this will teach you where you need to be positioned on the road, how to use your eyesight to make sure drivers pay you attention and other useful techniques that can minimise dangers. See: How to make your next bike ride safer than the last.
What should we do with our human weakness?
John Sullivan’s findings and suggestions are excellent. However, they rely on drivers changing well embedded habits. Personally I believe that, unlike RAF pilots, a driver is very unlikely to change their behaviour. Therefore, I’d suggest that this is another reason we should be looking at building safety in to our roads, with Dutch style cycling infrastructure.
Two important takeaways for cyclists: Increasing your contrast helps you be seen. Think flashing bike lights. Also, remember the importance of good road positioning.
So, I just read this article, and sent it to a few cyclist friends. However, I advocate steady lights (I favour lots of steady lights instead – like a Christmas tree :-), I have lit spokes, at least two lights each at the front and back, and high vis gear)
Here is the argument for steady bike lights:
Flashing lights only have one real advantage – as mentioned in the article – they are more eye-catching in a saccade. BUT flashing bike lights greatly diminish a driver’s ability to make accurate judgments of relative speed and distance.
Basically, flashing lights make it difficult for the eye to track a moving object.
In dark circumstances, flashing makes it hard to estimate distance, and if you are looking at a flashing light, it’s hard to estimate how its distance changes. Since the eye can’t adapt to the changing light circumstances fast, visibility is greatly reduced. (side note, this is different for emergency vehicles – there is a combination of lights and SOUND – which a bike doesn’t have- and drivers are expected to slow down and STOP, so that’s a different situation for flashing lights)
Steady lights are easier to see when moving – when it is vital that a driver can judge a bicycle’s relative speed and distance.
In traffic, as a car approaches from behind the driver should see the taillight and recognize that there is a bicycle. But this is only useful if the driver can perceive exactly where the bike is, and how its moving, and how much space it needs. With a constantly illuminated taillight, this is easier.
With a flashing taillight, it is much more difficult to locate the bicycle, its type of movement, speed, and the amount of space it needs
Also, a flashing light can distract the driver so they focus on the light instead of the situation at hand, ie. sharing the road with the bicycle, this makes overtaking more dangerous.
Other cyclists are also distracted by flashing backlights, especially if it’s really dark. Flashing lights make it harder for their eyes to adjust to the conditions of the road around them and impairs their ability on the road.
(Note – this was taken from numerous online sources)
Sure that’s all true at night, but in daylight?
Partly agree Liv. Use both; have a steady and a flashing lamp. This overcomes the problem of the other road user not being able to judge the range of the flashing lamp.
Why argue the merits of steady vs. flashing lights? I usually have two different rear flashers and a single front flasher any time I’m riding in traffic, and steady lights at night or in poor visibility. They serve different purposes – flashing attracts attention, steady shows your position. I’m not usually a dayglo and helmet wearer (although I do own a helmet and some dayglo gear) but I think it’s worth investing in something better than pound-store lights and using them often.
Agreed! Flashing lights are just annoying for those cyclists coming in the opposite direction. Or it should get flashing and steady every now and then.
I’ll still with flashing lights!…if I can pick them out with my eyesight then it’s a good bet that others can too!……and I’m happy to take a fighter pilots advice any day of the week!…😎
In Sydney anyway, the vast number of commuter cyclists and especially those on road cycles (more serious) wear black Lycra, and I’m at a loss to get why.
You want stay invisible to cars ?
My cycling buddy reckons it’s purely because they figure they look thinner in black.
He reckons we should hit em with “you look fat in black mate “.
It just might save their life.
They ain’t invisible, no matter what they’re wearing. It’s just that Australian motorists are lethally incompetent and will blame anything. Please don’t help them excuse their killing.
Surely Liv,
if a motorist cannot judge exactly where a vehicle on the road is ie. a cyclist with a flashing light he would wait to see where the light is, not just look and think , oh a flashing light and just hope that he was ok and pull out ?
You’ve not seen many motorists in action recently, then? The Highway Code rule to “Drive at a speed that will allow you to stop well within the distance you can see to be clear” has been misunderstood as “drive into a space unless you’re sure something is in the way”.
That’s a good article and stuff I kind of new from common sense. As someone who cycles more than I drive. I never assume someone has seen me on my bike. Flashing lights much better. As when I drive it alerts me quicker to the presence of a bike. To say steady lights are easier to judge speed and distances for a driver on paper is probably correct. But apart from a few well trained fighter pilots what car driver amoung us can honestly say they could judge that information while out driving. As a driver I need to slow down as a cyclists I need to be seen more. I’m human being. Peace and love.
Another problem with flashing lights is that motorists will steer towards what they are looking at. If the driver has to Look at a flashing light a few seconds longer to see what it signifies there’s a greater chance of the motorist driving too close to the bicyclist or, in my case, the motorcycle operator.
Lots of good points – flashing or steady? I veer towards flashing, but, LIGHTS first and foremost. I’d also add, ride in a group and multiply chances of being seen. Tricky in city traffic, of course.
Flashing lights, the off period between flashes varies. Some of them have a long enough “off” for rider and motorist to travel many metres. If the “off” occurs when motorist is checking for clear road then what with that and the saccade – invisibility! I’d like to see more lights, flashing for attention-grabbing plus steady for constant visibility. . There are too many urban riders with one, feeble, front OR rear. Rear often obscured by rider’s coat or backpack. Dark clothing, nothing reflective. Little lights on spokes are great for showing up side-on. I do not know how practical they are for regular cyclists.
Cyclists are harder to see than pedestrians. They move faster, yet are smaller – half a torso on a thin stick (profile like a lollypop), As a motorist I am fearful of hitting a cyclist. I do my best to drive carefully, get a shock when at the last minute I see a dim inadequately lit moving figure through rain and darkness, in the cycle lane so “safe”. What about when they turn onto a road with no cycle lane, what about at crossroads and roundabouts?
It’s not so much that we don’t see them its the fact we’re not looking for them looking for cars or trucks and when there’s a bicycle sometimes a motorcycle it’s very difficult to see them with your mind The lore and California says that my mono cycles can drive down the lane between the cars to me this is insanity you know you’re not looking for a motorcycle to come in the lane between the cars so you’re not gonna act accordingly have a great day go Bliss
Did you know that punctuation can really help your communication efforts?
Iride in a small town and its rural surroundings. A steady back light looks too much like the reflective markers often found on bends and don’t draw a driver’s attention to the cyclist being a dynamic object in the roadscape. I therefore use two fast-flashing lamps. As a car approaches, the lights appear to move apart so the driver more easily perceives their rate of approach. At ghevfront I have a steady dipped beam so I can see an a small fast-flashing light, once again tonemphasise that im not a reflective bollard
Oh, and additionally, my kids gave me a new helmet last Fathers’ Day. It’s Day-Glo yellow and has a small red light at the back. Jury’s out on how effective it is but it’s probably positive.
Iride in a small town and its rural surroundings. A steady back light looks too much like the reflective markers often found on bends and don’t draw a driver’s attention to the cyclist being a dynamic object in the roadscape. I therefore use two fast-flashing lamps. As a car approaches, the lights appear to move apart so the driver more easily perceives their rate of approach. At ghevfront I have a steady dipped beam so I can see an a small fast-flashing light, once again tonemphasise that im not a reflective bollard
Oh, and additionally, my kids gave me a new helmet last Fathers’ Day. It’s Day-Glo yellow and has a small red light at the back. Jury’s out on how effective it is but it’s probably positive.
All the actions of the RAF pilots sound as solid as you would expect. But they don’t ask enemy pilots to fix flashy lights on their planes. (sorry for the snark)
The priority advice (paraphrasing Adrian’s response here) is quite simply:
Never assume someone has seen you on your bike. The rest is just chaff (if you’ll pardon the aviation pun).
Allow us to have rocket launchers on our bikes like you have on your plane and we will be safe from drivers that did not see us.
After that everybody will see us.