Well that's great you figured it out, that's an unusual bug, definitely something that's hard to test and catch yourself, I never would have even thought of it.
That's awesome that you have so thoroughly detailed the driving model for the game and have so many different factors playing into it. There's many racing games out there now and in the past that just don't achieve the fun factor and sheer joy of driving that Outrun captures, and what you've got going here. Sega sure made a lot of great racing games. One thing you have to be sure to add is a great game over screen, in the proud tradition of great Sega ones in Daytona, Sega Rally, etc. 😄