Thanks for the feedback. Access to locations is to some degree limited, although I can get shots with no fences in the way from many locations. For this one, no spectators could have been behind; I will have more opportunities in the coming season, and will also take into account a shorter reach to bring in more of the subject.
Some angles do offer the curves of the track, and I do have shots from those vantage points; this was the one angle where I was experimenting with the car in such a motion blur. The pit area is a tough angle, as I think the only vantage point is from the grandstands opposite, and may have some blockage due to walls.
Still, it's all a fun venture, and I appreciate the comments thus far.