This track is Dirtyrock Ridge, this is a modified version of Redrock Ridge with a lot of sand on the road and some other changes. To install it put "trk001" folder that you find in the downloaded Zip file into "C:/Program Files/Electronic Arts/Nfs3/Nfs3/Gamedata/Tracks" and replace the existing one. You are allowed to create a project using as a base my track but please contact me first on my e-mail "opusivgamer@gmail.com".
Visit my Youtube channel "Opus IV Gamer" (https://www.youtube.com/channel/UCoIje9MbCb2TOtrMmGttYNg) to see a lot of videos that I made on Need for Speed III Hot Pursuit and don't forget to subscribe to it for new coming videos.