While I was driving through one of the busy junctions in Hyderabad, I watched this police man running behind vehicles photographing them as they commited the offense. I belive that even this could be contested too since you managed to get only a photograph of the vehicle and it would be hard to capture the entire act of the offense being commited as it was a snapshot in time.
There was an idea to put CCTVs at traffic junctions but I am not sure how successful that was as the CCTV would not have really been flexible and the public would have got smart to not commit the offense at the traffic signal.
There is a new trend now that is sure to come to India very soon. Police in Manchester, UK are piloting new CCTV cars to catch drivers using their mobile phones or being otherwise distracted at the wheel. Watch this video from BBC to get an idea of what I am talking about.
This sure is an interesting new trend as they can now position the cameras pretty much anywhere. Hence if you are commiting a traffic offense you can be caught anywhere at any time.