Probabiltiy of Car Crashes

(Originally written at Thursday, January 8, 2009 at 2:11pm)

Here is one simple thing in life that you want to note it down. It's not such a common event happened in my life. When this happened though, it will naturally keep me in deep thought.

There was a electric outage in the 3-5 blocks I lived in. My place is very close to Mass. Ave. For non-Bostonians, it's a main avenue that connect several residential regions of Cambridge Massachusetts.

The electric outage caused me to do something a bit different from my normal schedule - I went to a cafe to read and stay there until 10:10 p.m. and decided to walk back. The road is slippery. I nearly fallen down for a couple of times. But well, no big deal I just find the most snowy to put my steps on. Things are ok.

Then I heard a "bam" from my back and I took a look. 6-7 feets behind me, it turns out a van has lost control and hit on a building. Part of the wall has a 1 feet x 1 feet x 1 feet size of hole. There is a part of the building was made of steal. There is a dint. Luckily the car wasn't going too fast. So it just stops after it hits the building.

I am fair in my faculty of imagination. "What if I was hit?" and allow me to skip the description of my imagination because it doesn't look good.

I naturally wanted to leave that spot immediately. At the same time, I wanted to keep an eye on the driver and see if he was hurt. The driver gave me an "ok" gesture. Then he seems to get a grip of his wheel again. So my conclusion is the road might be too slippery and caused the whole thing.

For me, living is U.S. in general means a lot of thinking and philosophizing. Since I live with books and computers too much, I seldom come that close to a near-death experience. But I guess for many, any car accident in their lives will make them think.

Some might decide that's the moment to take up a belief. You will hear that in a lot of convictions from Bible study group or evidence of religion A, B, C. In my case though, I was thinking of the probability of how often this would happen to me.

According the car accident statistics, http://www.car-accidents.com/pages/stats.html, there are around 2.8 million people get hurt annually and 40k people died in car accidents. If we assume 330 million as U.S. population. So we are talking about an odd of 117:1 and 8250:1.

Now what are the odds of being hit and die if you are just walking on the road. (i.e. you are not a driver or passenger). Then according to statistics, there is only ~100 persons who will die like this. So the odd is around 1 million to 1 against that happens.

So 117:1 against me to get hurt makes me feel relatively happy because 117:1 is more like two consecutive drawn out by a 4 outers in Texas Holdem (~1/11). That happens often when you played 100k hands of holdem.

What about the other numbers? well, it sounds like I am naturally protected from dying anyway. In 8250:1, we are talking about someone who 4 consecutive drawn outs by a 3 outters. In the case of 1m: 1 case, that's so unlikely which lightning turns out to be more threatening to my life.

Now what about the fact that there is an electric outage and the slippery road condition, will that increase the chance of accident? Absolutely. It probably double the chance.

So what did I learn from this? Walking was statistically safer than driving. This doesn't take a PhD to figure it out. Well, but the fact that a lot of people change their life perspectives just because some unusual life events is astounding. After some semi-careful analysis, it is not such a mystery at all. These are just usual fact of life.

The event does urge me to search for a girlfriend/companion. (Umm, I don't know the probabily of *that*) Well, after all, if I live till 60, probability will dictate, there will be 1 or 2 days I will get hurt in a car accidents. Before that happens, let's make sure I have a family first. :)

Arthur