Why would you say that? A rich person would not spend hours every day commuting though rush hour traffic, or spend most of their day inside their work vehicle. They would buy or rent a central home, possibly near the central office building where they work. City driving in itself makes for a very low quality of life and most rational people would minimize it, given the option.

So I would expect there's either no driving-income correlation, or it's inverse. So reducing congestion would make life easier for rich people, who don't care about the money and only care about the time - by pricing out people who are, by definition, poorer and can't afford to buy that convenience. You could say that the resulting post-tax distribution is progressive, the rich paying and driving more; but that's just a way of distorting the initial argument, that introducing a flat congestion tax is strongly recessive - to the point of completely pricing out poorer people.