Do you have a citeable source for the claim that the underground pays for the roads? You often hear drivers that claim more rights because "they pay for the roads".
London Underground does bring in more revenue 2.864bn than it spends 2.041bn, and subsidises Streets and Buses to the tune of 0.889bn (with a little coming from media revenue too).
Drivers don't pay for the roads - any more than smokers, drinkers, or anyone else that opts into a 'sin tax' pays for the roads. Vehicle duty & fuel tax both go into "general revenue", and roads are paid by local councils.
"[road tax] was formally ended in 1936 after Winston Churchill asserted the following:
[I]t is a monstrous assertion that any important body of taxpayers should claim proprietary rights over the particular quota of taxation which they contribute, and that all should not be brought into an area freely justiciable by the House of Commons."
(aisde; a driver claiming to have more rights to roads because they pay extra tax on fuel, would be like a smoker claiming to have more rights to healthcare because they pay extra tax on tobacco products. I can imagine that wouldn't be popular. "General revenue" is supposed to disconnect source from sink to avoid exactly this.)
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London Underground does bring in more revenue 2.864bn than it spends 2.041bn, and subsidises Streets and Buses to the tune of 0.889bn (with a little coming from media revenue too).
However it isn't the 80% claimed above.
Time to find out this: about 1 minute.