Paul S.,
I also feel that the markings on the DIMS aerial photo are a bit off the mark.
One thing everyone must realize, with the exception of I-35...everything about DIMS was re-contoured...from the lake to the overall property appearance.
The shot you have is a little too close for me to tell for sure that the marked portion is the race track. I do know it was much closer to I-35 than indicated in the original post.
If you could find a wider shot...might be easier for me to spot. When I was traveling so much for NHRA for so many years, the approach to DFW took us over DIMS about 70 percent of the time. It was fascinating to watch how it was reshaped. Now, from that vantage point, unless you knew exactly where to look, you would never guess.
MaC