...for a dynamically-dispatched taxi- and jitney-centric urban transit network for around a decade, but I imagined it slightly different:

(1) You press a button on your terminal (mobile phone, 99.99% of the time) saying, 'I need to get somewhere'

(2) You pick your destination -- usually from a list of your top destinations and common endpoints, or adjusted from those as necessary.

(3) This 'want' (a request-for-bids) is posted to all alternative service systems, and they come back with options (bids), listed by price and travel time. Travel time estimates are *very* accurate, based on historical data, current fleet positions, and latest traffic info. So your list might be:

(a) $19 taxi picks you up +3 mins, reach destination +15 mins
(b) $10 walk 2 blocks east, get jitney +5 minutes, 1 stop, reach destination +22 minutes
(c) $1.50 walk 3 blocks north, wait 13 minutes for train X, 5 stops, walk 2 blocks west, reach destination +35 minutes

(4) You pick one (accept the bid). Payment is automatic with partial or full refunds if travel time promises are not met. Your handheld authenticates the vehicle that picks you up and reports back pickup/travel/dropoff data to the necessary clearinghouses.