There's two things I've noticed about the taxi driver photo ID's that are mounted on their dashboards in Shanghai; 1) the higher the number of their ID or license, the more recently they got their license and the less experienced they are, 2) if they speak some English or have other skills they are awarded stars that go on their license or ID. The most stars I've ever seen in Shanghai was a four star driver - he must have been the equivalent of a taxi Admiral. On the rare ocassion that I find a taxi driver whose license is in the very low digits - say 5,000, I feel a certain amount of awe because such a person has survived driving in Shanghai for something like 20 years. From the photo here, you can surmise that my driver had started his taxi driving career earlier this morning.

There's one more thing I've noticed about the photo ID in taxis - the driver often doesn't resemble the photo at all. I asked about this before and was told by a local that taxi drivers often ask friends or relatives to take a shift for them - or even let other's sublease shifts from them. Everyone's an entrepreneur here.