My wife and I both work around Hammersmith / South Kensington, she has a parking spot at work so we drive in every day and she drops me off. This costs us approx. £12 a day. If we were to take a train and public transport, that cost would be £80 per day.
Add in delays, cancelled trains, strikes, etc and you can very quickly see why I loathe our public transport system as much as I do.
For payment, just stick it in the price of fuel, like many other countries already have in place. That being said, this is the UK so they'll add it in to that cost and still keep the other costs we already pay.
Honestly I'm looking more and more abroad, I wouldn't be surprised if we emigrating in the next few years, this country has been circling the drain for years.