Coming with the 0.5 update next month is a track creator. As the name suggests, this tool is going to let you create your own tracks! When released it will still be in early stages and as such you will not be able to get the tracks fully setup in-game, however you can playtest your tracks with the press of a button with a variety of different environment presets. You also have options for which team and speed class you want to use in playtesting!
This track creator is now being used to create the offical tracks for the game, the editor is based on letting you place down each segment of the track individually. Tools are provided to make this no where near as tedious as it might sound, with options to automate the process of creating and rotating mass amounts of segments.
We can't wait to see what people do with this editor :)