Minibus taxis are staples of the "public" transportation systems all over Africa, from the Cape to Cairo. They're called combis in South Africa, matatus in Kenya, tro-tros in Ghana and, um... I dunno, I guess they're just minibuses in Egypt.
They generally run set routes, which are not posted in any way. Passengers know which minibus to get on because they know the local system. The way they work here, a guy hangs off the side and hisses or shouts the name of the destination, and people wave down the minibus they want. In South Africa, passengers use hand signals to tell the drivers where they want to go, and if the combi is going there, the driver stops.
The system's a little different at taxi ranks for long- and medium-haul minibuses. They leave when they're full. You walk around the taxi rank till you find a minibus going where you want to go, get in, and wait for more passengers. You hope they get there soon, because you can wait for hours if you're not lucky. You can buy more than one seat, which (a) gives you more space (really! it does) and (b) fills up the van faster.
Our commuter trains seem to STOP when they're full... "Any economic unit can emit money. The serious problem is to get it accepted" Hyman Minsky
For long-distance trips, private companies organize tourists into "VIP" busses (and boats, etc) with elaborate logistic system. But passenger's comfort is not a big priority. My trip from Bangkok to Samui island took 15 hours either way, including changes and waiting times. Government "VIP" busses (and higher class trains) are presumably more comfortable.
