That's just silly. It's not a money making exercise. Why do people always say this. If you don't want to contribute to the 'money making exercise' then just don't speed.
It is considered that by many because the variable speed limits are not used on the basis of safety / traffic flow alone - a motorway should be a 70mph limit unless there is a reason to reduce it for safety reasons - the choices being made are not geared around safety - therefore it is seen as a money making exercise - there is a reasonable assumption for motorists that motorways will by default be 70mph, so it will catch some out - perhaps the less observant ;) but still - if the reason for choosing the limits is not safety, it is reasonably to ask what they might be...
I know the M4 well and that stretch of road is very dangerous. It curves round relatively sharply in places and has several slip roads close together that are quite short so some traffic may have difficulty getting up to speed (eg lorries). It's also a very built up area so a reduction in speeds contributes to a lowering of pollution - both noise and exhaust.
really? a motorway has construction guidelines on bends etc - they just don't build motorways with sudden abrupt bends! There is no issue making progress at the speed limit along any part of the M4 - equally there are guidelines on building the slip roads - and I am pretty sure those guidelines are being met - a lorry has a reduced speed limit anyway, and an inability to accelerate along a slip road is not going to be improved by changing the motorway's speed limit...
the question of pollution has I think been recently disproved - yes, pollution levels from traffic go down, but they stay in the area longer, meaning overall levels are higher... think about the logic - a car going past a mile of motorway at 60mph will be in that area for one minute... now have it crawling past in a traffic jam at 5mph - it will be in that zone for 12 minutes - do you really believe that overall it will be less polluting for that zone?
But what about the car in front of you or the car next to you. Or like I posted above even the car in the opposite direction. All sorts of things could happen.
valid point - but you can only mitigate risk, not remove it - and risk will be managed far more by observation levels improving than speed being changed - while reports of accidents are 'it happened immediately, I didn't see it' etc. - in fact looking at accidents, the majority may well have shown signs before happening, e.g. a tyre bursting may split first making the car move suddenly - then burst pushing the car out of control - good observation would pick up the first symptoms and give time to do something...
equally - observation and risk management mean that you drive to the context or environment - a higher speed means you give more space / more time / etc. - so actually if driving well, you should be further away from anything where the tyre goes pop...
of course, someone driving fast and badly is a totally different issue...