Nobody has set a verified lap on the Grand Prix layout yet. Time a session here and your best clean lap goes straight to the top.
Start the lap timerTrackism re-times each lap from its GPS trace and only counts it if it follows the layout, passes every sector in order, has no gaps in the GPS, has believable speeds, and the start/finish line sits on the track.
Sectors are three equal lengths of the lap, and purple marks the fastest of each. Phone GPS is accurate to about two tenths, so very close times are a tie in practice. The board updates every few minutes.