Not sure the AI is quite right in places. If you look at the following (amusing video of 2 Americans new to F1), when they set the AI to Legend it almost seems as though some of the AI wait for you to catch up or won't pass.
See from 34mins:
(from 38 if you want to skip the preamble)
#7990835, By bluenicks Official F1 2011 (Codemasters) Thread
bluenicks 11 posts
Seen 19 hours ago
Registered 10 years ago