It would be nice to have the option for "racing traffic" on race track maps like Hirochi, as with the current traffic system cars will drive both ways down the racetrack. Maybe a system could be implemented so that race track maps have a "spawn racers" option for AI Traffic that will follow the track and maybe drive at racing speed? Maybe this could be a configurable option for time trials? (number of opponents, type of cars, driving aggression, opponent respawn on/off). I would love to be able to simulate a "Public Driving session" on Hirochi like they do at the Nürburgring!
The best way to do this is to make the AI flee on the track, they will go at racing speeds and they don't always go away from you.