eldan_bike (![[info]](http://l-stat.livejournal.com/img/userinfo.gif){kind=small} eldan_bike) wrote,@ 2005-05-12 15:31:00 |
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Being seen by drivers
Being seen by drivers is obviously one of the most important issues in cycling safely on streets. I had started writing some visibility advice in response toibm's post looking for bike-buying advice, but I moved it here because I realised it's relevant to all cyclists.
A few pieces of advice on accessories, based on cognitive psychology research I was involved in a few years ago:
OK, I think that's it for now, so I'll stop lecturing. I'll probably make more safety posts over the summer though; it's one of the things I had always been meaning to do with this journal.
Being seen by drivers is obviously one of the most important issues in cycling safely on streets. I had started writing some visibility advice in response to
ibm's post looking for bike-buying advice, but I moved it here because I realised it's relevant to all cyclists.A few pieces of advice on accessories, based on cognitive psychology research I was involved in a few years ago:
- Get a high-visibility jacket, even though it makes you look really stupid, and wear it whenever drivers are using headlights. Drivers' perception is very finely tuned to only notice things that look big, and the little point of light from bike's lights gets filtered out too easily, so the more of you that shines in headlights the better. I've also found that drivers actually give me more space when I wear the stuff, for reasons that are not clear to me.
- Don't skimp on lights. If your lights are brigher, it makes you look closer to a driver, which makes them more likely to give you space.
- The more horizontal distance between your leftmost and rightmost point of light, the more you look like a car to the primary visual cortex, so the higher a priority your signal gets in a driver's visual processing. If possible, separate lights with some space between them are idea (I do this on my handlebars), but this isn't always practical (especially at the back), so failing that just go for the widest light you can find. It gets a measurably faster reaction from drivers.
- Use your lights if it's overcast, raining or just dusky. Cyclists often overestimate how visible we are to drivers, and the more we do to help drivers, the safer we are.
- Don't use lights in bright daylight; especially not beam-casting headlights. There is a situation (basically if you are between the sun and a driver) in which this actually makes you less visible, because your overall brightness is closer to that of the sky.
- Do get a beam-casting front light, and point it slightly downwards. In theory LED lights are sufficient if you live in an area with street lighting, but in practice street lighting is seldom good enough to see all features of the road far enough ahead to anticipate them. The more you can see, the less likely you are to end up swerving to avoid a branch or grating or [this is a big issue in Cleveland during mating season] a small mammal corpse.
- For a combination of reasons I've mentioned above, get multiple reflective things. Reflective trouser clips are good, reflectors on wheels and pedals are good, and so on. They're all secondary to lights, because reflectors are only bright if light hits them at exactly the right angle, but it still adds up to more points of light for a driver to see you by, and understand how far away you are from.
- Please please please pleeeeeeease don't use those silly flashing settings that most bike lights have. They are worse than useless. Though the flashing does attract more attention, it has the unfortunate side-effect of drawing drivers' eyes so much that they drift towards you, and are less likely to see what's going on on the rest of the road. That latter thing may not sound like such a problem, but if a driver suddenly notices a car they are in danger of hitting, they'll swerve abruptly to avoid it, even at the risk of hitting you. It sounds evil, but it's rational really: a car-on-car collision is a lot more likely to hurt the driver than a car-on-bike collision, and unconsciously we do prioritise threats in that selfish a way.
OK, I think that's it for now, so I'll stop lecturing. I'll probably make more safety posts over the summer though; it's one of the things I had always been meaning to do with this journal.
