It worked fine for me. I forgot about it until last Saturday, then I plugged in my phone and was up and running quickly. I was on a public road, not a track, but it still tracked my location and route while recording vehicle information and video from my phone's camera (I have a windshield mount that quickly let's me clip my phone to it with a magnet).
Pretty cool. Really ideal for a track but if you have a stretch of road you drive a lot you can record info there too (all while staying at or below the legal speed limits, of course).