So, had some fun at the drag strip today. Put together a video of one of the runs. 2014 Tesla Model S P85D vs 2015 Nissan GTR Nismo - YouTube And here is the PerformanceBox graph for that run: Here is the time slip (frame used for my video): Now, I can't seem to reconcile the two sets of data. They seem to differ by about 0.5s (PBox always showing a higher time) I was posting about this in another thread, but I didn't want to derail it. At first I though the times were off by my reaction time on the slip (0.516s)... maybe this is the case, but I have another run with a 0.224 reaction time on the slip that has the same 0.5s difference from the PBox. The ~0.5s difference appears to be pretty consistent. For this run: 60' Time PBox: 2.16s Track: 1.626s Difference: 0.534s 330' Time PBox: 5.32s Track: 4.788s Difference: 0.532s 1/8th Mile Time PBox: 7.96s (@ 94.82 MPH) Track: 7.356s (@ 95.003 MPH) Difference: 0.604s Now, I went and analyzed my video a bit. The reaction time appears on the board in the distance exactly 15 frames after the green light on the tree comes on... so, 0.5s, which matches my slip. However, my car has definitely moved several feet by the time this happens. PBox says almost 3' and almost 8 MPH at 0.5s. So... any ideas? Is the track wrong or is the PBox wrong...... they can't both be right. Edit: Some more Google searches landed me this quote: "Most drag strips will not start timing until your vehicles wheel fully crosses over the start line, which means the first foot of movement will not be captured in their official time." Guess that could explain it. PBox says at one foot I was traveling at 4 MPH after 0.4s.