That is definitely a rig shot, but there is also a heavy edit on the photograph.
This particular photog failed to edit the boom out well. Look specifically at the hood/fender line on the driver side as it approaches the headlamp assembly. It's all flubbed up. You cannot go half way with these rig shots, either you will invest the time to edit or you will fail badly.
The sky is also an edit, you will not light a car on the shadowed side the way this has been done and get a flare of that nature. I'll admit the flare edit is far better than the rig extraction.
The blur looks pretty accurate for a rigged shot. The closer your back drop is, the more motion the frame will feel. If objects are way off in the distance they will not blur as much.
There's some discussion of my rig layout and a shot of it in set up on my bagged suburban here:
http://www.moddedmustangs.com/forums/pictures/283400-how-do-you-do.html
Swift, when you extract the car for a faked roller - you gotta watch your edges. The pavement around the tires and the edges where the white paint transition to background are a dead giveaway. I would extract the car in two layers, first one right on the edge via a manual selection at 200% zoom for accuracy, second bump it out 3 pixel widths. of course apply your BG motion blur to the background layer and then phase back in the extracted cars. The 3 pixel bump lays first remove set your eraser to opacity of 30% and erase to the edge of the car as cleanly as possible. Lay your last car extract layer on top of that. Then use your blur tool set to 5% and run it around the edge of the car, not too much, you want to keep as much sharpness as possible.
All of that will stop that tack sharp pavement and paint blur you see around the edge of the car. The rig cuts down on 50-75% of this type of chop time.