回复：BMW midsize 应该和 Toyota midsize 比

I agree that for the Front Offset tests, comparisons should be made only within a vehicle "class", if the concern is head on collisions. However, a comparison can be made between classes for other types of collisions, (like hitting a stationary object, or another vehicle not head-on.) I am currently summarizing the data for the actual probability of the various types of fatal crashes, and will post it later.

The results for head-on collisions are effectively "normalized" because the vehicle collides with a stationary barrier. (although there is actually no real normalization of the results, since they use the same acceleration requirements for predicting injury, regardless of the vehicle.) The side-impact results, however, are not "normalized", and comparisons can be made, regardless of the vehicle "class."

In general, I think that the definition of a vehicle "class" is somewhat subjective. Should the Honda Civic and the Nissan Altima really be in different classes? There is only about a 400lb difference in mass. My original table includes vehicles which range in mass from about 3100lbs +/- 700lbs. I think this is a reasonable range for comparison, but you might make a good argument that it is too large.