In message , at 18:17:47 on Mon, 5 Oct 2015,
tim..... remarked:
It's not necessarily important for every private hire vehicle to
offer disability access, because the are pre-booked. As long as each
firm has some minimum number of such vehicles available if requested,
that should be sufficient.

That I understand

but unless that "minimum number" is somewhat larger than you might
first calculate, you either end up with the accessible cabs waiting
around all day for the one disabled passenger, or no accessible cabs
free at the time that passenger turns up.

It's queuing theory 101, not that difficult.
--
Roland Perry