I peeked at some statistics, and it looks like there were around 4,000 fatalities involving large trucks. Out of (I'm assuming this includes commercial vehicles) 35,000 total vehicle fatalities.

11% is not nothing, but it's also not the 89% chunk.

Long stretches of boredom punctuated by split-second reaction moments also describes my driving... and I can do that in anything 5 tons or under without any sort of regulation (except a passed driver's license test some number of years ago).