I've had more trouble with ****** entry level BMW drivers than trucks personally. I bought a Garmin Varia.
I will say, the faster you ride the nicer folks seem to be. I average around 20 including all the hills on my routes, meaning I cruise flats around 22 to 23mph. Folks seem to have less issue with that than when they encounter somebody going like 12mph.
Not sure why. So maybe, train up!