Below are several different videos found by Mauricio of the same accident. No details on how this effects production. While often there is multiple copies of a car, one for stunts, one for a camera rig, and so forth, that doesn't necessarily mean they have more than one of the "hero" car which is usually the vehicle that is used for close-ups and whatever scene that is required were the vehicle just has to look good. They might be able to rig another copy or even get the car repaired in record time by swapping parts with other vehicles. The last video is a shot of the aftermath found by TFormers as 'Bee gets prepped for towing. Thanks to Richard, @sdlrob, and the many other site readers for the info.
Update: According to Colin Hinkle, who shot a lot of the cool images and videos from Chicago, he spoke with crew then and learned that Transformers 3 production does have two hero cars, one with tinted windows to help hide the driver and one without.
Update 2:: J1000, who brought us all the images from Detroit, provided this picture to back up Colin's info. Two Bumblebees, the tinting being the only difference. In addition, Todd C. who was onsite at the time of the accident reports:
I had taken my kids to the American Indian Museum and walked out to see them shooting. I was right there when the accident happed. The one thing they are not explaining is that this was the second take. The first take the corvette was behind Bumblebee and lost control and spun around nearly colliding with a trailer. So the next time they put it behind Ironsides so it would not have to make a sharp turn. In between the 1st and second shoots, and ambulance also went through scene. It didn't seem like he knew what was going on. He got half way through then kind of slowed down by Optimus Prime looked at it confused then kept going. believe me it was a big mess!