Here in the UK if your car is accused of speeding by an automated device (e.g. a roadside unmanned camera or a "talivan")
then the local police for the area will obtain the name and address of the registered keeper - basically the person deemed to be the keeper of the vehicle - from the DVLA.
The registered keeper is then asked to identify the driver at the time of the alleged offence so that they can be charged - there is a limit of 28 days for this. There is a fine for non-compliance, and the RK can also get 6 points on their licence - 12 is a ban.
This leads to two possibilities. Firstly if the RK is being forced to identify themselves then this perhaps comes under the legal rule about self-incrimination which could make this clause unenforceable. Unfortunately our "friends" in Europe decided this was not the case.
Quite why they should be asked to decide is a whole different (political) debate. - see the situation with Greece at the moment
Secondly the wording of the act states that the RK must take "all reasonable means" to identify the driver. But if they can't, then no charge can be made. Of course this phrase is quite open to interpretation by the court. If the RK can convince the court they have no idea who was driving then they are safe.
Most camera pictures are from the back of the vehicle making it difficult to identify the driver, so the RK simply says "no idea" and explains why it may have been 1 of a number of drivers - shared driving etc.
For company vehicles it was suggested they had to keep a record of who was driving but this was thrown out as the responsibility for being insured to drive is on the driver and not the owner or RK. One guy who owned an engineering company asked the court "if a screwdriver owned by my company had been used in a murder would that be my responsibility ?" - the case was thrown out.
Of course to challenge all of this you need the pictures and in some cases the video evidence. The latter has been hard to get hold of as the police sometimes claim it contains details of other people (i.e. registration plates) and therefore breaches their privacy but as I can see a reg plate on the street anywhere that is rubbish. Some of them try and impose a charge too.
All of this means than eventually the case ends up being abandoned but of course a few thousand £s are wasted beforehand - for a fine of maybe £60 in some examples.
My boss has had his speeding case of 3 years go through exactly this. He is up to hearing 8 or 9, everyone has to be there (police operator, lawyers, judge) each time and each time it is adjourned again. At the last hearing it was abandoned. How much was wasted on that ?
As for speeding I'm with James May - "Don't be a prat". 80 in good weather on a motorway is not dangerous, 25 in an urban street with kids could well be. We need cops to decide, not cameras.