How drivers’ brains will try to kill you

The dreaded SMIDSY explained

Drivers don't usually want to run you over, but their brains may have other ideas

Not being seen on the road is one of the easiest ways to come to a sticky end. The problem is that doing the obvious things, like using lights and wearing bright clothing, just isn’t enough, because the human brain does some very clever things that have the unfortunate side-effect of making you invisible to drivers.

That’s the topic of this video by Canadian motorcycling channel Fortnine. While it’s aimed at riders of bikes with engines, the phenomena being discussed are equally relevant to cyclists.

Did you know for example that your brain effectively takes a series of images as you pan from side to side, rather than scanning continuously?

These images are the result of your eyes moving in a series of jumps called saccades and the result is that it’s possible to skip over dangers completely, effectively not seeing them at all.

If you’ve ever experienced a SMIDSY (“sorry mate, I didn’t see you”) despite a driver seemingly looking straight at you, this might well be why.

Fortnine’s Ryan explains this issue with help from some amusing graphical demonstrations and then delves into related brain weirdness including selective attention, peripheral blindness and more.

It’s sobering to think even drivers who think they’re being attentive may unwittingly not see you at all, but armed with that knowledge you can adapt your riding and hopefully minimise the potential for unfortunate encounters.

Incidentally, if you’re interested in a slightly more cycling-specific examination of the saccade problem, this article by RAF pilot John Sullivan is well worth a read.

Stay safe out there, people.

Matthew Allen

Senior Technical Writer, UK
Former bike mechanic, builder of wheels, hub fetishist and lover of shiny things. Likes climbing a lot, but not as good at it as he looks.
  • Discipline: Road, with occasional MTB dalliances
  • Preferred Terrain: Long mountain climbs followed by high-speed descents (that he doesn't get to do nearly often enough), plus scaring himself off-road when he outruns his skill set.
  • Current Bikes: Scott Addict R3 2014, Focus Cayo Disc 2015, Niner RLT 9
  • Dream Bike: Something hideously expensive and custom with external cables and a threaded bottom bracket because screw you bike industry.
  • Beer of Choice: Cider, please. Thistly Cross from Scotland
  • Location: Bristol, UK

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