Thanks for the info. This time I did use shortcuts. The fastest AI lap I saw was just under 1:16. My best lap (using shortcuts) is a 1:15.29, and in the video, I run a 1:15.43. I forgot to stay in 3rd gear on the next to last left turn (downshifted into 2nd), but this only affect time by about .1 second.
Still, after getting a descent lead on the shortcuts, the fastest AI is gaining fairly steadily from that point to the end of the lap.
Another trick that can be used on the last lap is to slam into the lead AI car on one of the last 2 hairpins. Usually the AI gets stuck for a while.
I settled for 2nd on the road to success 6. Only 14 more events to go, may get done by this weekend.
The shorcuts on Miami 19, especially the 2nd one were fun, reminded me of my old Need For Speed 4 - High Stakes days, where the game intended for you to take some very narrow shortcuts at high speeds to get the best lap times.
Link to video of the last lap of on the road to success 5 using shorcuts.(1:15.43).