Here's an interesting approach to public transport. Mexico DF is very advanced on a project called Metrobus, a combination between buses and metros. Its main advantage is a 'cleaner' organization of the traffic, causing reduction of need for cars and a better service of buses.
The vehicles look like buses, but the difference lays in the stops, which are set in determined points of the city, like metro stations. Undefined stops cause traffic disorder, and this would guarantee a better fluid of passengers and more efficient service, with corresponding decrease of the number of public vehicles needed. It's assumed that this will lead to lowering the levels of gas emissions. It works with a pre-payed card, so that the driver doesn't have to worry about anything else but driving, and front door is only used for entering and back doors only for exiting, so transition time is greatly reduced. People involved in the project include Treehugger featured Emiliano Godoy, who is working on the visual signs for the stations.
Brazilian state Curitiba's former Mayor Jaime Lerner succeeded in a similar project called Ligeirinho (Quickly) Auto Bus System, which came into use in 1991 and became so efficient that it's now utilized by 75% of the citizens. ::Metrobus. [by Paula Alvarado, from Buenos Aires]
Schemes of the look of the stations
Emiliano Godoy's project for street signing