Law Enforcement

I am in the main a law abiding citizen.I do admit to at times riding at a little over the limit however always when conditions 'permit' However, I am becoming slightly concerned at the number of people I see obviously breaking some 'serious' laws. I refer to mobile phone use, seatbelts speeding in built up areas. If I, and others, see these on a regular bases why does it seem so hard to bring these people to justice. Could not a PCSO be positioned at a road junction and simply photograph these people? Maybe I am seeing the situation from a too simplistic angle, or maybe more than one person needs to witness the offence. I have reported incidents about dangerous driving but always told it has to be seen by someone else. This, is I assume to protect their 'human rights'. Happy days.