Joined Feb 2008
804 Posts | 0+
Devon
Question: What do the following items have in common?
A stealth Missile
A Predatory insect
A motorcycle
Answer: They are all invisible when hurtling towards you.
The age old mystery of why perfectly sane motorists pull out in front of approaching bikes – and then stop suddenly in their path – could be closer to being solved. Recent scientific findings suggest that motorcyclist can become almost invisible to drivers as they ride directly towards them. New research has revealed how a principle called “motion camouflage” can make bikes blend into the background and vanish to a driver directly ahead.
A related optical effect called “looming” makes them visible again at the last minute – but this makes the driver momentarily freeze in his tracks.
A motorcycle approaching a side junction can effectively become invisible to a driver waiting there to pull out. This is due to a startling effect called “motion camouflage” that fools the eye into believing the moving object is stationary. It happens when a rider travels down a line that extends from a fixed point behind the bike directly to the eye of the driver waiting at the junction ahead. The riders size does not appear to increase as they travel down this line and so they blend into the background. As a result, the driver is not alerted to the presence of the bike because his brain is scanning for movement. Finally, as the bike nears the car, an effect called “looming” occurs – which is where the bike suddenly grows in size, destroying the motion camouflage and becoming visible to the driver. But a natural response to the looming means drivers are momentarily frozen to the spot.
Motion camouflage was first described in1995 (Srinivasan and Davey) and the therory that hoverflies and dragonflies use the technique in aerial battle was confirmed a couple of years ago. Now missile engineers are replicating the strategy to make ballistics harder to dodge. But it was only recently that the link was made to SMIDSY (Sorry Mate I Didn’t See You) accidents.
The insects’ motion camouflage technique takes advantage of a natural brain response to the “looming” effect. Looming works on the part of the visual cortex that uses “edge detection” to to alert us to the presence of movement. If no edges are detected, no alert is triggered. So, if the driver sees the busy urban scene up the road, made up of many static blocks of shape and colour, and your in it, apparently not moving, the driver is simply not being alerted to your presence. Until we loom into view, that is!
It’s the sudden change in size that alerts the eye to the approaching object. Unfortunately for bikers, but to the benefit of bugs and bombs, the “uncloaking” effect of looming occurs when the moving object is very close to the target.
Looming is also a key factor in an animals “fight or flight” response and is preceded by a momentary “freeze” phase in which they make themselves physically ready for action. Researchers have found that you can “freeze” a rabbit just by making a shadow on the inside of its cage rapidly expand. The effect works the same way on humans. This is a possible answer as to why so many drivers start to pull out and then stop, frozen to the spot, having seen us suddenly loom into their vision.
According to Police crash date, in nearly all SMIDSY accidents the bike has hit the car somewhere between the A- pillar and the front wheel, This suggests the point at which we “loom” into view is very close to the junction and the car. Also, the fact that drivers start to pull out and then see us, suggests the driver’s own movement has nullified the motion camouflage effect by separating the rider’s outline from the background, thus improving their ability to detect edges.
So what can we do to prevent it?
There has been no official research into this yet, but it is clear that you have to make yourself visible. We have to look for ways to increase visibility beyond the headlight and reflective tabard. If you follow the collision line or at least remain close to it, you will gradually veer from the normal riding line (to the right of your lane) towards the kerb. This will maintain the motion camouflage effect. By keeping yourself away from the collision line, and remaining in the safe riding line (towards the right of your lane) will cause you to diverge from the collision line sooner, destroying the camouflage effect earlier.
So it follows that our normal safe riding position is our best position on the road. But there is another way of alerting the driver to your presence much earlier along the collision line. A smooth gentle zigzag motion, at any point along the line, creates a rapid edge movement and destroys the motion camouflage. Driver’s eyes will snap towards you the moment you make the movement. However, I would be careful suggesting a weaving movement as overdoing it could spit you off.
Riders must use a common sense approach and adjust their riding to the prevailing conditions. If unsure, the best advice to take from this is, there’s potentially another reason why motorists don’t see us, so be aware and slow right down when passing junctions.
And surely the irony of all this is, come summer, when the hoverflies are splatting across your visor, you can chuckle in the knowledge that it’s probably their own killing strategy that stops them seeing you until the moment you “loom” them to a mushy death.
A stealth Missile
A Predatory insect
A motorcycle
Answer: They are all invisible when hurtling towards you.
The age old mystery of why perfectly sane motorists pull out in front of approaching bikes – and then stop suddenly in their path – could be closer to being solved. Recent scientific findings suggest that motorcyclist can become almost invisible to drivers as they ride directly towards them. New research has revealed how a principle called “motion camouflage” can make bikes blend into the background and vanish to a driver directly ahead.
A related optical effect called “looming” makes them visible again at the last minute – but this makes the driver momentarily freeze in his tracks.
A motorcycle approaching a side junction can effectively become invisible to a driver waiting there to pull out. This is due to a startling effect called “motion camouflage” that fools the eye into believing the moving object is stationary. It happens when a rider travels down a line that extends from a fixed point behind the bike directly to the eye of the driver waiting at the junction ahead. The riders size does not appear to increase as they travel down this line and so they blend into the background. As a result, the driver is not alerted to the presence of the bike because his brain is scanning for movement. Finally, as the bike nears the car, an effect called “looming” occurs – which is where the bike suddenly grows in size, destroying the motion camouflage and becoming visible to the driver. But a natural response to the looming means drivers are momentarily frozen to the spot.
Motion camouflage was first described in1995 (Srinivasan and Davey) and the therory that hoverflies and dragonflies use the technique in aerial battle was confirmed a couple of years ago. Now missile engineers are replicating the strategy to make ballistics harder to dodge. But it was only recently that the link was made to SMIDSY (Sorry Mate I Didn’t See You) accidents.
The insects’ motion camouflage technique takes advantage of a natural brain response to the “looming” effect. Looming works on the part of the visual cortex that uses “edge detection” to to alert us to the presence of movement. If no edges are detected, no alert is triggered. So, if the driver sees the busy urban scene up the road, made up of many static blocks of shape and colour, and your in it, apparently not moving, the driver is simply not being alerted to your presence. Until we loom into view, that is!
It’s the sudden change in size that alerts the eye to the approaching object. Unfortunately for bikers, but to the benefit of bugs and bombs, the “uncloaking” effect of looming occurs when the moving object is very close to the target.
Looming is also a key factor in an animals “fight or flight” response and is preceded by a momentary “freeze” phase in which they make themselves physically ready for action. Researchers have found that you can “freeze” a rabbit just by making a shadow on the inside of its cage rapidly expand. The effect works the same way on humans. This is a possible answer as to why so many drivers start to pull out and then stop, frozen to the spot, having seen us suddenly loom into their vision.
According to Police crash date, in nearly all SMIDSY accidents the bike has hit the car somewhere between the A- pillar and the front wheel, This suggests the point at which we “loom” into view is very close to the junction and the car. Also, the fact that drivers start to pull out and then see us, suggests the driver’s own movement has nullified the motion camouflage effect by separating the rider’s outline from the background, thus improving their ability to detect edges.
So what can we do to prevent it?
There has been no official research into this yet, but it is clear that you have to make yourself visible. We have to look for ways to increase visibility beyond the headlight and reflective tabard. If you follow the collision line or at least remain close to it, you will gradually veer from the normal riding line (to the right of your lane) towards the kerb. This will maintain the motion camouflage effect. By keeping yourself away from the collision line, and remaining in the safe riding line (towards the right of your lane) will cause you to diverge from the collision line sooner, destroying the camouflage effect earlier.
So it follows that our normal safe riding position is our best position on the road. But there is another way of alerting the driver to your presence much earlier along the collision line. A smooth gentle zigzag motion, at any point along the line, creates a rapid edge movement and destroys the motion camouflage. Driver’s eyes will snap towards you the moment you make the movement. However, I would be careful suggesting a weaving movement as overdoing it could spit you off.
Riders must use a common sense approach and adjust their riding to the prevailing conditions. If unsure, the best advice to take from this is, there’s potentially another reason why motorists don’t see us, so be aware and slow right down when passing junctions.
And surely the irony of all this is, come summer, when the hoverflies are splatting across your visor, you can chuckle in the knowledge that it’s probably their own killing strategy that stops them seeing you until the moment you “loom” them to a mushy death.
:biggrin:biggrin:biggrin
