both need addressing - that's the point, but I think we see it a lot closer than it first appears ;-)but in that case it's this that needs addressing - not people doing the school run.
At the end of the day I see what's in front of me first. You can't drive through Leamington or Warwick on a school day, at school in/out time - the 2 adjoining towns are completely blocked up, and a 2 mile journey takes an hour - cycling is quicker at these times.
Myton Road (has 3 schools) can take >45 minutes on its own and it's one of only 3 routes from Leamington to Warwick. On school holidays at the same time there is never a problem.
Some towns have introduced park and ride for shoppers, but none that I know of have done it for schools, because there is no money to do it. Businesses get stung for business rates that fund these things - Schools do not as they are mainly funded from local tax moneyanyway, so there's no point trying to tax them.
At the end of the day, car tagging might help the problem a tiny bit by penalising parents who don't want their teenage kid to use their legs, but I can't see it working to any great effect on any group of road users. It seems to be fundamentally flawed in my simple way of looking at things.
For a congestion charging to work, there needs to be congestion. If the system were to remove congestion, then the roads would be free, no penalties applied for using certain roads, and the traffic will come back (that can't work...). So all that will be achieved is a compromise between traffic jams and those who can afford (or can't avoid) to pay.
Nobody wins but everyone has to pay for a high tech gadget and the additional cost of administration (which could be seen as 'everyone looses')
Just my low tech view on it. I'm not saying I'm right - I'd gladly be proved wrong!