There are quite a lot of lorries, trucks, and vans on the road right now with exactly this, with diagonal red and yellow stripes. Do a google image search for "

There are quite a lot of lorries, trucks, and vans on the road right now with exactly this, with diagonal red and yellow stripes. Do a google image search for "rear reflective chevron" for examples. I think it's a great idea, and would love to see it on more vehicles. The main disadvantage is that the road by contrast may become harder to see. But I'd argue that the road also needs to become way more reflective, on the painted lines. The paint itself has some amount of retroreflective material, but it rapidly gets dirty. Cats-eyes are fabulous, but they also need to be regularly maintained and replaced, and that has definitely been slipping in many places.