At some point in the past, Yellow Freight acquired or merged with Roadway Express, which was orange.

why are yellow trucks orange:

https://www.myyellow.com/us/en/about-us/extra-mile-blog/why-...

"Swamp Holly Orange" is a great name for a color.

I could see myself calling that color a dark yellow. Doesn't look red enough for it to really be orange; but of course color is in the eye of the beholder. ;-)