Why Motorcycles Appear To be Invisible to other road users!

……….sometimes

See also: Road Safety Campaign – “‘Give motorcyclists a second thought”
Another TV advert by TFL (Transport for London) that warns drivers of the dangerous ‘optical effect’ that can lead to collisions with motorcyclists

???In addition to the very interesting explanation of ‘motion camouflage’ below another ‘phenomenon’ that may account for some instances of SMIDSY (Sorry Mate I Didn’t See You) may well be ????????????Target fixation / Motion induced blindness. Of course it’s important for motorcycle riders to be aware of these issues not just from the point of view of not being seen by others but in relation to failing to see potential dangers ahead themselves!
There’s a good example of how motion induced blindness works here:
http://www.msf-usa.org/motion.html
Target fixation is a term also used in another sense for motorcycle riders, a basic principle of motorcycle riding is that you go where you look, concentrate your vision anywhere other than where you intend to ride and you could end up with an off road excursion!

Google phrases such as: motorcycle target fixation and motion induced blindness

“Motion Camouflage”

Well one explanation is a principle called ‘Motion Camouflage’ which may explain why motorcycles / motorcyclists / bike riders appear invisible to car drivers in certain circumstances.

In fact having done a bit of research on the Net there is nothing new about motion camouflage and I know many of you will have long ago adopted techniques to try and avoid it – change of line as you approach junctions, flapping jacket, moving your head etc

All the same the article that appeared in Bike Magazine March 2005 is interesting and useful to newer riders…………

Apologies for the quality of the scans, just found the images on my PC but not had time to see if I still have the original mag pages to rescan.

Click the following two images to see enlarged:

Summary:
An article in the March issue of the UK magazine Bike added a bit to the understanding of why cars pull out in front of motorcycles. Research on how certain insects attact prey was applied to the SMIDSY crash (sorry mate, I didn’t see you).

When attacking, a dragonfly stays directly in the line of sight between its potential dinner and a fixed point in the distance. If dinner moves, the dragonfly alters its path just enough to stay on that line of sight. It doesn’t swoop out to “lead” its victim. This tactic has the effect of keeping the dragonfly at the same point in the prey’s visual field. Because the prey sees no change in the big picture, it is unaware of the impending attack. This is called motion camouflage.

Motion is difficult to perceive when it is directly along the line of sight. Because the object is stationary relative to the background, an observer doesn’t see a change in the overall image and thus isn’t cued to the presence of a moving object. Though the object increases in apparent size as it nears, the change goes unnoticed at first–moving from 1000ft distant to 900ft may not affect the image enough trigger a response. A motorcycle is particularly susceptible to motion camouflage because its cross-section area as seen by an observer is much less than that of a larger vehicle.

But as the object gets closer, apparent size increases more rapidly. At constant speed, an approaching object takes the same time to move from 200ft to 100ft as it did from 1000ft to 900ft, but the apparent size increase is greater. Eventually the object seems to grow suddenly in size, and the motion camouflage is broken. This is called the looming effect. According to the Bike article, when an observer is startled by the looming effect, he may freeze in his tracks. If the observer is an oncoming left-turner, he may stop in the middle of the intersection, making a bad situation even worse.

Duncan MacKillop, the riding instructor who related motion camouflage to motorcycling, suggests that diverging from the direct line of sight will break the motion camouflage and get the observer’s attention. For example, a driver stopped at a cross-street on your right will be looking left at a slight angle to the path of the road. If you stay to the left of your lane, you will diverge from his line of sight, making yourself more noticeable. But if you’re veering right (say, moving from the left to the right lane) you’ll be moving along the crossing driver’s line of sight, helping to hide your motion against the background.

MacKillop recommends: “I observed a smooth, gentle, single, zig-zag motion, at any point along the line, created a rapid edge movement against the background and destroyed the motion camouflage. Drivers’ eyes snapped towards me and they froze the movement I swept left to right and back again.”

Don’t Take It In – Ever glanced at your watch and had to look again because you didn’t register what time it is?………………… SOMETIMES A QUICK GLANCE ISN’T ENOUGH! (mp3 audio file)

Reference / Links:

http://www.dcs.qmul.ac.uk/researchgp/spotlight/motion_cam.html

‘Motion camouflage’ on Wikipedia:
http://en.wikipedia.org/wiki/Motion_camouflage