The thing with raising congestion charges, higher taxes on airfares etc is that you then limit these options to the financially well off, which doesn't seem very progressive.
Even in the US, where car ownership is practically mandatory and broad taxes or fees on driving are significantly lower, owning a car is associated with higher incomes because the base cost is still several thousand a year in insurance, gas, etc. so if you tax it you are already hitting wealthier people.
I don't see what's progressive about letting private cars clog the roads up and slowing down London's vast and comprehensive bus network.
The wealthy are always able to buy the nicest things, and addressing income inequality is a very valid goal. But what realistic alternative is there to the price mechanism that still allows for a level of individual choice, and permits vehicle journeys that are economically necessary (e.g. tradespeople) while discouraging car journeys that could me made by other means.
As for the minimum wage earner, they are the least likely to be able to afford to keep a car. The current roads free-for-all means their bus journeys are far slower due to the traffic, and more expensive due to the larger number of buses required to maintain frequency on congested roads.
A possible solution to reduce inequality from road charging while still maintaining the benefits of the price mechanism would be to return the proceeds (after maintenance costs) to the residents of the city in the form of transport credits. These credits would be able to be spent on road access, public transport, or cycling as the individual preferred.
> The wealthy are always able to buy the nicest things,
the problem is that there is no product differentiation when it comes to road usage. You're either on it and paying the same fee, or you're not.
It's not like food, clothes, housing where you might be paying a lot for these things, or you might be paying less. We price specific items of food without regard to income, but there's a wide variety of items of food to choose from, at different price levels.
Not so with a lot of transportation.
In the context of a large city, there certainly is differentiation in transport. You can grab a large amount of the scarce road space for yourself with a car (even more if you park on-street) or taxi, or you can take a smaller share of it by getting on a bus, bike or tram.
If you buy more/better clothes you end up paying more. You also end up paying more to upkeep said clothes.
If you consume more water, you end up paying more for it; Progressive water pricing is very common around the world.
A progressive road usage pricing scheme would not be out of the ordinary.
Use routes that other people use and get it cheaper, have the private low use roads cost more. As poor people are more likely to live in denser areas it would be cheaper for them.