And as long as we are going off-topic, could anybody help answer this question? Its from an old friend of my finishing up his Ph. D back in the states.

I was hoping that I might ask you for a small favor that would really help me out with a research project of mine. It goes like this: I am interested in how the license plate number allocation system works for those who own cars registered in Beijing. I presume you know a few people who have cars registered in Beijing and I was hoping that you might informally ask them how the process went when they were down at the DMV: what sort of choice were they given in terms of the license plate number they could get for their car? If they had a choice, did they choose in light of some of the recent restrictions on what days they could drive (i.e. based on trailing license plate numbers)?

If you know a few folks who you could just informally ask, I would be appreciative. If you have any questions, I would be happy to answer them. At the moment, I just want to see if the system works the way it is supposed to according to the descriptions on the GongAn Traffic Bureau Website.

Sweet, thanks much Jon.

Yes, the interest is currently with automobiles. The basic idea is something like this: since April 2010 you have had so-called "no driving" days in Beijing in order to control traffic and air quality. The system has been Monday - Friday, and each day automobiles with plate numbers ending in a pair of digits are not supposed to take to the road (ex. if your license plate ends in 1 or 6, then you cannot drive on Monday; 2 or 7, Tuesday; etc.). However, underlying preferences can severely effect the efficacy of such a public policy measure.

As I said above, this measure is designed to control traffic and air quality by hypothetically taking 20% of the automobiles off the road on any given day. However, this result is based upon the assumption that the distribution of license plate numbers (in terms of the trailing digit) is uniform. But what happens when Beijingers/Chinese choose cell phone numbers, apartments or anything else with a numeric sequence? Many actively avoid choosing sequences with 4 or 7 and actively seek to choose numbers like 6 8 and 9.

As a cultural specific preference, this may very well feed into the selection of plate numbers (presuming there is meaningful choice about your plate number). If this occurs on a broad enough scale, it should result in a non-uniform distribution of plate numbers on Beijing automobiles. Furthermore, the effect may be measurable in terms of outcomes like daily air pollution measures that pick up vehicle exhaust, traffic volumes and other information that is available down to the daily level within the city. Start plugging that up to something like daily hospital intake rates for respiratory conditions and you have an interesting story.