Post a trip or book a seat between Jordan's governorates.
Intercity ride sharing for Jordan: Amman, Irbid, Zarqa, Aqaba and everywhere else. Drivers post the trip they are already making; passengers book a seat on it.
Intercity travel in Jordan runs on 'service' cars that leave when they fill. You go to the station and wait, with no way to know whether that is ten minutes or an hour.
This moves the matching online: a driver posts the trip they are making anyway, passengers book seats on it, and both sides know the departure before anyone leaves the house.
Problem
A seven-seat car with two people booking the last seat at once is the normal case on a popular route, and overselling means someone is left at the station.
Solution
Remaining seats are decremented in a single server-side operation rather than read-then-write, so a race resolves to one winner and a clean 'full' state for the other.