Probably not much use to many of our vistors but for those GrandPrix1.com visitors or anyone else who still plays F1GP, someone has created a Track Editor (currently in 1.0 Beta). It's DOS based and I have yet to test that it actualy works. There is some discussion about it on the forums in this thread.
Apparently somone else is working on one as well. You can see a screenshot here - it's windows based so this one may be easier to use.
It has been about 10 years since the release of F1GP but we finally have a track editor for it. Grab the track editor here.