[Conquistador]

Originally Posted by pete-p

I do wonder also, and it may not have made much difference, but why did the trailer not have guard rails to help prevent cars from going underneath?

There are no U.S. national regulations for trailers having sideguards believe it or not, just rear rails. It's only in the last couple of years that city-owned vehicles have been fitted with them. Boston, MA was the first, then NYC.

If U.S. trailers have them already fitted, the chances are it's in the interests of pedestrian and cyclist safety in the cities. The rails would have to be upgraded and redesigned quite substantially to be suitable for reducing fatalities like this.