I think so as well Robin, thinner frames to crumple in during a rear end collision may save some ones else life. Far back as the 60`s though the first thing to rust out on truck frames were the rear portions, not sure it was a crumple zone back then but my dad had a 75 Ford that the rear frame rusted out before even the steel box bed did. We cut er and put a low mileage Dodge frame to er, welded on about a foot right behind the cab, exactly the same width between frame rails, nevah told the vehicle inspection stations a thing....LOL