And this Ladies and Gentlement is why our increasing reliance on "machine justice" makes a mockey of the both the legal system and peoples attitudes to that system!
In the old days, a real policeman would have stopped you, had a chat, applied some common sense based on the actual situation they observed. Depending on those circumstances, and how the accused handled the incident, chances are you'd be on your way with a warning, and a mental note to yourself to be more observant next time. Job done, point made.
In 2014, a machine measures your arbitary speed in an arbitary situation, and if speed > (limit+leeway) sends you the bill in the post.
At no point is there any human interaction, the perpitrator ends up "hating" the system for penalising them for something that in their mind was incredibly minor and it erodes their confidence in both the legal system and also is, imo, actually more likely to make them miss the entire point of the speed camera in the first place.
(most peoples reaction to a camera fine is not "i will drive slower" but "i will keep a better lookout next time"!!)
So, gradually, drivers faith in the legal system is eroded, and people who actually drive poorly, dangerously (which is actually completely independant of the speed at which they happen to be moving) and without courtesy to others continue to drive in that fashion.
So, whilst the law HAS to be black and white (<30mph = ok / >30 = speeding for example) we have lost the "grayscale" filter that a real human being used to apply.
This has meant that we now have a much much greater reliance and importance on the setting and maintaining of appropriate limits than before.
For example, immagine in extremis the following situation.
20mph zone, directly outside school gates, with a speeding camera set to fine you at >22mph (20mph +10%).
At 3.30pm on a schoolday, when the road is full of cars, parents and kids, i will drive past at 20mph exactly. But, unfortunately, i'm smashed off my tits on a mixture of alcohol, hard drugs, and not only is my car on fire (my spliff set fire to the passenger seat....) but both rear tyres are flat.
At 3.30am on Sunday morning, you drive past, doing 23mph. No one is about, the road is empty. You car is in perfect condition, you are not only driving well, but courteously, and you have recently passed your advanced driving test with the IAM.
Now, who would like to tell me that in both cases a human would respond in a similar fashion to the machine?
In case 1, with machine justice, i'm off scott free, in situation 2, you're getting a Fine and some points.
See what i mean