Because the bottom of a truck is higher than the bumper of passenger vehicles, when there is a collision the smaller vehicle easily slides under the truck and the first point of impact is the windshield — resulting in underride and passenger compartment intrusion (PCI). Seatbelts, airbags, and car crumple zones do not function as intended in underride crashes — front, side, and rear — leaving passenger vehicle occupants vulnerable to life-threatening injuries.
This geometric mismatch has been misunderstood for decades. Reports on truck crashes generally focus on the cause of the crash and not what caused the deaths. So underride is undercounted. I know this from firsthand experience having been in a truck crash (but not in the part of the car which went under the truck) and lost two daughters because of underride (one of whom was not reported as such in DOT data).
In order to raise awareness and preserve the memories of underride victims — precious ones gone too soon — I have been writing memorial posts on what appear to me to be underride crashes. I am not a crash reconstructionist, and I do not have all the facts on these crashes; but underride should be investigated as a potential factor in truck crash injuries and deaths.
This is not an exhaustive list — merely the tip of the iceberg. But I hope that it serves to demonstrate the ongoing nature of a preventable public safety problem.
You can find these Underride Crash Memorial posts here.
Certified Letters Alert 200 Carriers of Underride Dangers & Solutions