Using smart phones!
It is interesting to notice that the police use some iphone to take pictures of the license plates and send them directly on the police network!
Traffic police efficient work.
In China the traffic police does a great job. There are too many cars who park everywhere, endanger pedestrians and other drivers. It is a good thing that traffic police become less and less lenient.
In order to avoid corruption, traffic policemen come from different location. In the south of China there are the policemen from north China! In north China, you find policemen for south China!
Also when the police stops your car when you drive drunk, they will immediatly take your mobile phone away. Thus you can not call anyone to threaten them!
It is interesting to see that the Chinese traffic police pretends to lock the car wheel so that they can fine them.
In fact, according to the law, they should lock the car wheel. But they can not do it. There are too many cars who park illegaly. There is too much traffic and it would be too much work for the tow truck to handle!