An excellent overview, one thing I'd like to take issue with is this: We can also observe that, in the IIHS analysis, many factors that one might w

An excellent overview, one thing I'd like to take issue with is this: We can also observe that, in the IIHS analysis, many factors that one might want to control for aren't [...] One way to see that the numbers are heavily influenced by confounding factors is by looking at AWD or 4WD vs. 2WD versions of cars. They often have wildly different fatalty rates even though the safety differences are not very large (and the difference is often in favor of the 2WD vehicle). Some plausible causes of that are random noise, differences in who buys different versions of the same vehicle, and differences in how the vehicle are used. I have no idea why that is either, but the author is surprising confident in declaring AWD a confounding variable, especially after the earlier "Actual vehicle tested may be different" point they made. A typical AWD will have a transfer case, front driveshaft and other front drivetrain components v.s. a sister car in a 2WD configuration. The overall weight and distribution will be different. One might e.g. suspect that in a crash the front driveshaft might fold upwards and assist in structurally compromising the passenger cabin.