I recall that when San Francisco retrofitted its city buses so that all are accessible to people using wheelchairs, an economic analysis showed it would be cheaper for the city taxpayers simply to provide free taxi service to all wheelchair users. The reason for putting people who use wheelchairs on city buses seems to have been wholly political--to mainstream such persons into a form of transportation that makes them more visible to other members of the public (at least, the members of the public who use buses).

I have both an emotional reaction and a rational reaction to this policy trade-off. On the one hand, my own late father was confined to a wheelchair as a quadriplegic (after a slip-and-fall accident on an icy parking lot here in Minnesota) for the last six years of his life. So I totally get why friends and relatives of persons who use wheelchairs want public places, and by extension public transportation, to be accessible to persons who use wheelchairs. That allows many more family outings with grandparents and their grandchildren than might otherwise be possible, for example. But my rational reaction is still that we all have to work hard to pay our taxes, so "public" money (money derived from taxation) should still be spent responsibly. If devoting taxi service (and, I hope, someday a self-driving car service) with public subsidies helps needy members of the population more than bus service, so be it. Spend the least money to get the positive externality is generally the way to go in public policy.