Infinite money pot.
The government in this country seems to view the car owners in this way. The reason that so many cars are on the road is that public transport is, in many cases, not a viable alternative.
A lot of the congestion comes from the poor quality of the roads, the fact that they are being dug up by one company after another and poorly repaired afterwards. It's a wonder you don't see workmen waiting for the hole to be filled so they can dig it up again.
This is used as a way of ensuring a budget by some companies. If you had £3m to spend on maintaining your phone network this year, but only used half of it, then you may only get £1.5m next year. So why not pay for a huge hole to be dug in the middle of a busy road, leave it for a few weeks, then fill it in again. As most companies can state how long they will disrupt the traffic, and there is no governing body with the power to say "This is how long it will take, finish by this time or don't start", they can take as long as they like.
Stop digging up the roads and leaving the works unattended, and this may improve the congestion. Get the traffic moving and maybe public transport will become more viable (I know this is not the only problem, and a lot more investment is needed, but hey, it's a start!).
If the money raised by taxing car users was only allowed to be spent on the roads, there would be no point in introducing all the new taxes (once we have nice shiny gold plated roads, with a seperate lane for each car!).
So far we have:
Car tax (to use the roads)
Impending Pay as you go tax
VAT on the purchace of the car
And now the added joy of not being able to find a parking space that you don't have to pay even more for (one tax for when the car is moving, another for when it is stationary!). This, in turn, brings in more revenue for local councils in parking fines. In my area, to park within a three mile radius of my home costs £1.50 per hour, plus £60 a time if you are late getting back to your car.
Why do I own a car you may ask?
Have you tried getting around by bus? is my reply.