When late, I think I might like a taxist, for double fare, to drive me from this omnibus station to that omnibus station before the next onmibus would. If that omnibus would arrive sooner than the taxi, my ride is free, becuase the taxist did not fulfil the condition of the contract. Perhaps have a clause that, if the taxist, rather than abandoning the passenger in mid-route, drops me off at one of predetermined locations (e.g. an earlier omnibus station), then the taxist is paid an amount, relative to the omnibus fare, proportional to how far he drove me. (e.g to ride the next omnibus, walk, or try again with a next (possibly this) taxist).
Presently, negotiating this sort of complex agreement would take too long for it to be useful, but if my computer were doing the negotiating, I might have some options ready when I arrive at the source station; all that I, personally, would have to do is choose the one that I think is best (or I might configure my computer to choose which is best, and I need only confirm).