Terry Labonte had the same problem at his transporter. He casually exited the side door of the transporter, went around the front, and back to his car unannounced to the fans gathered at his rig. Don't get me wrong, autographs aren't all bad. Granted, I haven't asked for an autograph in over two years since I began my media job, but the ones I did ask for were at autograph sessions before I gained access to the pit and garage areas of tracks. But even if I were still an autograph person, I would venture to say that the best time to ask for autographs is not during the hustle bustle of a busy track during the day, but before or after the day begins.
Drivers tend to have more time and are more relaxed then.
They're not busy with their jobs. A little standing around never hurt anyone. I've had to wait many times for interviews with drivers, and I was kindly rewarded with a quality conversation. It parallels the Microsoft software developer. If he's talking with the boss after work on the sidewalk, don't interrupt them, that's common sense.