Go to Par Park area over off of Hall-Johnson, not bad runs there. Also try off of Brown Trail in bedford, a street called Mayfair Hill Court is a badass run, real fast.
I try to go to DFW airport as much as I can; go to terminal D and do the parking garage, top (6th) floor to the bottom (2nd basement) floor. It is real fast, try to do it without braking/carving/stopping