DUI

we all know DUI is bad, so why some of us still drive after drinking? I had dinner in the city with friends last weekend, and of course drank some. I took a cab home and left my car in the city. The cab fare is about $40, the garage parking cost $30. I came back to pick up the car the day after cost $10. Total cost of not driving was about $80. Quite a lot of money, considering the dinner/person was about $50-60.

The probability of being caught is small. Surfing the web suggest that the cost of first time DUI is not too high in California either. The exact penality is different in each county, but is about 3-5 years of court probition, $1,400-$1,800 fine, 6 months loss of CA License, DUI school and 48 hours jail time (may be replaced by social service).
http://www.kandblaw.com/penalty_chart.html#first

Lets do some guestimation: The median income for a 4-person family in CA is about $68,000 (2003 US census). Suppose 2 of 4 are working. Each work 52 weeks in a year, 40 hours a week. This translates into $16.3/hour. Average commute time for a typical San Franciscan is about 29.2min (2002 US census). Suppose during the 6 months of license suspension, you double your travel time. 6 months loss of CA license costs extra $8 a day, or $1,040 for the 6 months (26 weeks x 5 days x $8). DUI school costs about $50. 48 hours (2 days jail time) loss of income $260 (16.3 x 16 hours). These sum up to $3,150. Don't know how much costs for the probation. Lets all round up to total cost at $4,000.

Put this together, the probability of being caught should be about 0.02 to make a risk neutral driver indifferent between driving or not driving. I would guess the actual probability of being caught is way lower than that. I guess that is one of the many reasons why people DUI.

I have heard that the accident rate in US is higher than Germany, why? I have also heard that some areas in Germany have no speed limit, any correlation there?

Another thing I notice is that in some cities, car is a luxury goods. Only wealthy people can afford a car. Public transportation is good enough to accomodate most prople's need. In this case, those with cars are wealthy people. The cost of having an accidient is high enough that they will drive safely. Accidient tends to be lower as a result. The accident rate in this case will drop more than proportional to the number of car on the road due to this selection process. This is another reason (in addition to lower air pollution) why we want to promote public mass transportation.

AN UPDATE: MSN has an article suggesting the cost of DUI is about $11,000, including car towing, future rise of insumance premium, attorney fee, etc. The probability then becomes 0.007. Is that good enough? probably still not, but honestly I don't know, but I do know many of us do not know this figure. The police may want to advertise the cost of DUI more publicly...