Zoom in! Zoom in! The background is distracting, and photos like this are typically cropped as tight as possible to minimize those distractions. Great subject matter and panning shot though!
Good photo. A faster shutter might've been better allowing you to capture the people in the background as well. (unless the car is going so fast to make that not possible, but I'm guessing it isn't since his arm is out the window) Good job.