Back in my NYC bicycle courier days (all two and a half months of them), I got into my share of scrapes. I got my front wheel smacked by a speeding car. I was forced into a turn by an oblivious van, and off the road by a reckless truck driver. I got doored. I got flipped off, yelled at, and threatened. But I never feared for my life.
Now I live in the sleepy village of White River Junction in Vermont, and let me tell you: I fear for my life every time I make a trip longer than half a mile. Seems counter-intuitive, doesn’t it? Not if you’re a cyclist. The reason: there’s strength—and safety—in numbers.
It’s pretty much the same in the UK, as I learned from this article  in the Guardian UK:
When I started cycling  in London eight years ago I felt I was virtually the only one, battling for space with taxis and buses. It was a fight with few allies. Today, things are very different – I’m one of the pack surging away at the traffic lights. Official figures show more miles were travelled by bike in 2008 than for each year since 1992. Cycling has almost doubled on London’s main roads in nine years and increased by 30-50% in cities such as Bristol, Leicester and Leeds.
But it’s really remarkable that despite the increase in cycling, casualties suffered by cyclists are still down by around a third. To anyone who doesn’t cycle this might seem a bit odd. Shouldn’t more cyclists mean more crashes and injuries? As those who cycle will know, however, the more cyclists there are the safer it will be for everyone.
CTC (the UK’s national cycling organisation)  found that the same phenomenon occurs if you examine different areas within the UK. Cambridge, where a quarter of people cycle to work, or York where it is about one in eight, have a much lower risk of injury for cyclists than places where you hardly ever see a cyclist on the streets.
Why does this “safety in numbers” effect occur? The vast majority of cyclist injuries result from crashes with motor vehicles, and most of these appear to be primarily because the driver “looked but did not see”. Cyclists (and motorcyclists) have even given this type of crash a name – Smidsy, an acronym for the drivers’ refrain, “Sorry, mate, I didn’t see you!”
These type of crashes start to decrease as cycling levels rise.
Take the hypothetical case of Bob the Driver, who last rode a bike when he was still in school uniform. Bob drives up to a junction with a major road, glances right and, not seeing anything car-shaped, pulls out into the path of the “unseen” cyclist. Crash and injury result. If, as Bob approached the junction, there was a stream of cyclists crossing in front of him, he probably won’t make the same mistake.
Photograph: Mikael Colville-Andersen/guardian.co.uk