A recent study by the Insurance Institute of Highway Safety (IIHS) examines driver death rates by car model. Although not the intent of the study, the data show a definite safety advantage for all-wheel drive (AWD) cars and crossovers, and four-wheel drive SUVs by comparison to similar models with just two-wheel drive (2WD). In fact, some of the best evidence is that even in the same vehicle, the AWD version has proven safer.
BestRide has looked very closely at this new IIHS study. From the years 2009 to 2011 there were just nine vehicle models in which no driver was killed. Seven of the nine models are AWD or 4WD (IIHS uses the term interchangeably, as do many manufacturers). The cars and SUVs that had 4WD and zero driver deaths were the Toyota Highlander AWD, Lexus RX 350 AWD, Toyota Sequoia AWD, Audi A4 AWD, Volvo XC90 AWD, Mercedes Benz GL-Class AWD, Subaru Legacy AWD. The Kia Sorento and the Honda Odyssey 2WD models also had zero driver deaths. This 7 to 2 ratio of AWD to 2WD models with zero deaths is just the first piece of evidence hinting that AWD is safer.
The report also shows the number of driver deaths per million registered vehicles for the 2WD version of some of these vehicles. For example, the Lexus RX 350 had six deaths per million registered vehicles in 2WD form. The Toyota Highlander had seven. The Kia Sorento 4WD is not listed, but its twin, the Hyundai Santa Fe with 4WD is on the list and had a rate of 12 deaths per million. Likewise, the Audi A4 is not listed as 2WD, but the similar VW Jetta in 2WD had a rate of 20. The Subaru Legacy had zero deaths and only comes with AWD, but there are many vehicles in its class with 2WD. Examples include the Accord (19), Camry (35), and Mazda6 (54).
Another piece of strong evidence is that the 2WD version of the Chevrolet Suburban, a giant of a vehicle, had an unusually high rate of 60 deaths per million. However, its 4WD version had a much lower fatality rate of 17. The Chevy Tahoe followed the trend with the 2WD version being about twice as likely to have a fatality. The Ford Expedition also follows the trend with the 4WD having a low rate of just 5 and the 2WD version having a death rate of 36. The vehicle size does not seem to matter. The mid-size Dodge Nitro 2WD has a rate of 51, but the 4WD just 13.
Not every single vehicle follows the trend. The Chevy Avalanche pickup 2WD (15) and the Avalanche with 4WD (29) show an opposite relationship. It is difficult to find another example that breaks the trend clearly though.
This is not the final word on 4WD vs 2WD safety, but view the list yourself and you will see that evidence is very strong that all-wheel drive and 4X4 vehicles show a definite real-world safety advantage over very similar vehicles that have only regular two-wheel drive.