Amar
There's an answer to all your points, from a politicians point of view anyway!
Many many moons ago the money we spent on using our cars (road fund license/vehicle excise duty, fuel duty) was ring-fenced for road network and infrastructure (incl public transport) - these days most of the money you spend in duty filling your car up gets spent on debt reduction/schools/hospitals etc etc as it's marginally more paletable to a politician than arguing why the basic rate of tax needs to be higher to cover the direct costs of running a country inefficiently (and it doesn't seem to matter which colour govt you have, none of them are successful historically at making things cost less to do!)
The road network is largely the responsibility of your local authority to repair, but their budgets aren't protected for maintenance so it gets spent elsewhere too.
The talk about 'private' new roads had me in stitches the other day - talk about recycling an old policy on road pricing and trying to make it more appealing to joe public! The QE2 bridge was supposed to be free to use once it was paid for and they're still campaigning for that now, years after it was!
Last point from me on public transport - as with anything there's supply and demand. At the moment we have excess demand in the south east, so prices go up. This pushes people to look at alternatives, until such time as the tax paid on those alternatives is so high that public transport looks appealing again. If everyone stopped driving and tried to use public transport it'd be hilarious for a day or two before everyone gave up and got back in their cars. Investment in new infrastructure for rail costs billions and because of the way 'privatisation' was done the tax payer more or less picks up the tab for that too, although to be fair the current lot are weaning the rail industry off its mega-handouts for running a profitable business.....
In effect nobody wins on transport policy as it's a brave politician that sets in train a policy that won't 'pay out' politically within their term in office, unless it's a 'glory' project like HS2 of course.....
Makes me glad I'm not currently involved lol