You are driving in the lane left of a semi-truck that is slightly ahead of you. It suddenly and without warning turns and cuts left across your lane. How much length do you have in which to even attempt to use the brakes?

I was in downtown traffic once, on the main drag, traveling at the posted speed of 40 mph. There was a large pickup truck in the lane to my left with his rear bumper about even with my front bumper. Then some idiot asshole in a panel van in the opposing traffic decided to turn left across our lanes of traffic, and I didn't see him until he had already crossed in front of the pickup, who had to jam on his brakes even seeing what was happening. I had, at best, maybe 20 feet in which to come to a dead stop without T-boning the van from a speed of about 60 feet/second. I made it with inches to spare (and this is an unpaid commercial for the quality of Jaguar brakes) and my calculation afterward indicated it had been at 2 gs. The passenger in the van looked out the door window and gawked. They continued on.

The Haitians had absolutely no chance of survival.