In urban public passenger transport buses, trams, metros and suburban railways or light rails prevail sustainably. Their common characteristics are that they are simple, reliable, and appropriate for city transport.

Buses are mainly used for the fine distribution in rural areas whereas trams (in big cities) and metros (in million- and mega cities) represent the backbone transportation lines. Generally, buses are often used as a compromise solution disregarding its strengths. Its main advantages are the low investment costs and considerable flexibility. Trams and metros are quite popular with passengers. Studies show that an extension of these kinds of systems always leads to an improvement of the modal split towards public passenger transport. Fully automated, elevated Automated Guideway Transit (AGT) like APMs, or monorails are only used sporadically as connector/feeder systems. Due to the derogation of the privacy (vehicle passing by close to windows of offices/private houses) in downtown areas and because of the high investment costs they are not very attractive for middle- and big cities. Only in mega cities where mobility with motorized individual transport is almost impossible several levels for public transport are necessary. This is where monorail lines can sometimes be found.

Environmentally friendly, flexible, comfortable transport solutions operating independent of the motorized individual transport will gain increasingly attention in the future in public passenger transport while the offer for pedestrians and cyclists will continuously be enlarged at the same time. Individual e-mobility or autonomous vehicles cannot solve the traffic jam problems in cities and encounters limits when trying to improve the efficiency of urban traffic. Even a green traffic jam still represents a traffic jam. The ongoing electrification of public passenger transport in combination with renewable energies will improve the current situation significantly and enables space saving mobility at the same time. New green transport solutions must be as powerful, available, flexible, and economical as successful passenger transport systems operating today to represent the backbone of modern urban passenger transport.