> That's still around a one in 4 million chance any given trip kills you, about the same as 30 miles of driving for the average American driver.
For those wondering if that is right, it is. Here's the math.
Americans drive about 3.2 trillion miles per year and about 40 000 people are killed. That's one death per 80 000 000 miles.
Assuming each mile is equally deadly, that chances you survive a given a mile would be 79 999 999 / 80 000 000. To survive a trip of N miles, you have to survive each individual mile sequentially. The chances of that would be (79 999 999 / 80 000 000)^N.
The chance of not surviving that trip would then be 1 - (79 999 999 / 80 000 000)^N.
For N = 30 that is 1 / 2 666 667, which is close enough to dmurray's number to count as a match. There's enough fuzziness is in the inputs that all we can hope for is the same ballpark.
I've seen others say the rate is one death per 120 000 000 miles, and for N = 30 that does give 1 / 4 000 000, so I'd guess they are using that rate.
> Most people would accept that level of risk. Perhaps not to save a couple of minutes on the journey, but if everyone was redirected to another route at rush hour, it might cost each commuter 10-20 minutes
One big difference is that with the bridge everyone has the average risk. I cross the bridge, I'm rolling a d4000000 and hoping I don't get a 1.
With a car I can take steps to make the chances of dying on my particular trip much lower than average. With the car I can often time my trip so as to go at times of day or during weather conditions or during traffic conditions when accident rates are lower.
For those wondering if that is right, it is. Here's the math.
Americans drive about 3.2 trillion miles per year and about 40 000 people are killed. That's one death per 80 000 000 miles.
Assuming each mile is equally deadly, that chances you survive a given a mile would be 79 999 999 / 80 000 000. To survive a trip of N miles, you have to survive each individual mile sequentially. The chances of that would be (79 999 999 / 80 000 000)^N.
The chance of not surviving that trip would then be 1 - (79 999 999 / 80 000 000)^N.
For N = 30 that is 1 / 2 666 667, which is close enough to dmurray's number to count as a match. There's enough fuzziness is in the inputs that all we can hope for is the same ballpark.
I've seen others say the rate is one death per 120 000 000 miles, and for N = 30 that does give 1 / 4 000 000, so I'd guess they are using that rate.
> Most people would accept that level of risk. Perhaps not to save a couple of minutes on the journey, but if everyone was redirected to another route at rush hour, it might cost each commuter 10-20 minutes
One big difference is that with the bridge everyone has the average risk. I cross the bridge, I'm rolling a d4000000 and hoping I don't get a 1.
With a car I can take steps to make the chances of dying on my particular trip much lower than average. With the car I can often time my trip so as to go at times of day or during weather conditions or during traffic conditions when accident rates are lower.