There are going to be big changes as we see an increase in not only electric cars but also self driving cars and a I suspect a lot more people using car share type schemes.
Less fuel duty and most likely revenue from speeding fines. Potentially much less accidents and much lower pollution related illness so maybe some savings for the government to offset the taxes.
I’ve not seen any figures yet but surely running costs for electrics cars should be much lower and when things steady out with 2nd and 3rd gen vehicles I can see depreciation slowing greatly so coupled with much cheaper servicing and much less repairs the knock on will be more disposable income so higher taxes elsewhere wont have as much impact.