Originally Posted by
wphamilton
Getting a precise number for accidents per mile is difficult because we don't know precisely how many miles are actually traveled by bicycle.
But I do know this much: estimates top out at 21 billion miles for cycling in the US per year. 726 deaths /21 Billion miles = 34. Data is good for auto passenger fatalities.
34 fatalities per billion miles traveled, bicycle
11.4 fatalities per billion miles traveled, passenger vehicle.
At the very least, since 21 billion miles is the very highest estimate for cycling, cycling a given distance three times more dangerous than driving.
The problem with
this is that most people spend much more time driving than they do cycling. "three times more dangerous than driving" sounds bad but it does't reflect how people really cycle or ride.
Distance, as I said earlier, is an unfair way to compare cycling risks.
Because people
tend to drive for more distance than they would cycling.
Assuming a 12 mph speed cycling and a 46 mph speed driving, then the risk per hour is the same.
That is, in practice (the real world), the higher average speeds when driving make up for the lower risk per mile. Because, on average, people in the real world tend to drive many more miles than they cycle.
It isn't perfect, but it's more fair to compare the risk-per-hour.
Originally Posted by
wphamilton
I know where you're coming from, half of US trips are short, 5 miles or less, and very short rides take about the same time as driving. But still, you're comparing the cyclist who seldom or never drives to the driver who doesn't bike. That IS one way to compare risks.
I'm not making that comparison at all (it's not possible to do anyway).
Originally Posted by
wphamilton
But I think that most people, me included, want to know the risk of riding to the post office vs driving there. I have a car in the driveway ready to go, bike in the hallway, and I'm going to Kroger. How much riskier, if any, to take the bike? I'm not saying that it's a significant risk either way, but to be honest it's at least three times the risk to cycle, more if we consider all injuries (and not just fatalities).
That's not "honest" at all.
On average, in the US, people drive 12,000 miles per year and ride a few hundred miles.
And the "three times" risk might not apply to you particularly at all (meaning the real/actual risk to you isn't "three times").
Clearly, if you never drive, you'd be safer driving!
Originally Posted by
wphamilton
How much riskier, if any, to take the bike?
You still really don't know. Keep in mind that your actions can drastically increase or decrease your personal risk relative to the average/aggregate risks we are talking about.