I have been watching this chart for as long as it has been on the internet -- it's great for finding vehicles which are cheap on insurance.

That being said, I see obvious self-selection issues show up in that chart all the time. Looking at the extremes usually points it out -- 'old man' sports cars usually have very low accident rates. Vehicles sold with deep discounts or aggressive financing deals usually have high accident rates. These are likely bought by very different buyers with very different life circumstances who use their cars very differently.