At first, TrackMaker may sound like a pretty specific and vertical workflow tool. However, if you are developing game and game assets, the task of developing something like a race track is something that has to be done over and over again for each level of the game.
TrackMaker is a collection of scripts for the 3dpackage Autodesk Maya, aimed specifically on the track creation process for games
Created by Bjorn Klaassen, TrackMaker for Maya takes care of all the components of creating racing game like tracks and roads while keeping all the objects dynamic relationships intact in Maya, making it a procedural way to create and edit the racetracks easily with the ability to create, texture, place and edit all with some easy controls.
TrackMaker also provides a suite of tools to assist in basic modeling functions in creating the terrains and basic landscapes for creating racetrack assets.
TrackMaker for Maya is a small price of 5.50 euros (5 euros + 0,50 paypal costs) Which will get you the plugin and support (hotfixes, patches and explanations) to get you started.