[toss1]

>>high off the ground (needlessly most of the time) they are more susceptible to rollover.

Also the far greater mass of the vehicle requires far stronger A-, B- and C-pillars to not crush in a rollover

Forcing all vehicles onto a 30-50% weight loss diet would help every factor tremendously, including reduced braking distances and more nimble turning to reduce collisions in the first place, reduced impact when there are collisions, reduced road wear, reduced fuel/energy consumption, etc.. Everything gets better with lighter weight, but engineers/designers seem happy to blow right past any weight budget at the slightest excuse (if there even is a weight budget in the design brief). The sheer mass of vehicles these days, even so-called "sportscars" never ceases to amaze me, and when it gets to SUVs and trucks, it's just insane. The technology certainly exists to cut weights by close to half, to levels of 35 years ago, and improve safety and performance while doing so.