All over Shanghai you can find traffic cameras hanging on light poles, bridges and traffic lights. If you break the traffic rules you are supposed to get a ticket if the police catches you, so most people watch out when they see a camera. So far most cabbies knew pretty well where all cameras are located (my driver is a former taxi driver and he has a good knowledge of them), but many others notice the cameras only when they see a flash or when they are in slow-moving traffic jam.
It seems the police decided that a wider knowledge of the location of these instruments might reduce the number of people breaking the law, so they now put all traffic cameras online. You can see all cameras in the city on Shanghai’s traffic police site. According to the website there are a total of 1739 cameras in Shanghai and hidden cameras, e.g. cameras that are not on this list, are not allowed. The camera locations were opened up to the public earlier this week, and a lot of people were eager to find out the locations: as a result the site had 4 million hits in the first 7 hours the police cameras were published there! I did not see any mash-ups with Google Maps or Baidu Ditu yet, I think that would be a big hit as well.