One of the best city building -- not to mention free-- games ever made, Mobility is an incredibly realistic traffic simulation by German developer Glamus that plays like a cross between SimCity and Transport Tycoon.What makes the game different than either of those classics is the ultra-realistic economic and traffic models that underly the game. These models are the result of the scientific support for the project by the Weimar Bauhaus University and the traffic research department of giant car maker DaimlerChrysler. Moreover, the measures that you can implement to affect traffic and the options for spatial planning, as well environmental impact of your decisions, are all based on professional models created by transport and urban planners. As Glamus touts on their website, "this means that the program technologies used in Mobility are completely new in the field of CD-ROM game production. Only with the help of such technologies was it possible to create images and situations that closely resemble reality."

Rock-solid traffic and economic models aside, Mobility is also pleasant to look at, thanks to the game's SVGA graphics and the ability to zoom in quite substantially. The interface takes some getting used to, but the learning curve is quite low. The interplay between your decisions and their effects on the game takes some time to notice, but once they become apparent, you'll appreciate all the research and work that goes into this game. Suffice it to say that the level of detail of realism makes Mobility ideal for actual classes in urban planning, much more so than SimCity. Definitely a must-have for every city builder out there. Two thumbs up!