I didn't mention reflective tape. For those who don't want something permanent on a showable preserved military vehicle (which all of mine are), magnets again come into play.
I buy magnetic sheet at the hobby/craft store and stick reflective tape to it. Most of the 3M tape I have is 2" wide, as it that red/white stuff you can get at the parts store. I like that that red/white stuff, it is incredibly bright, but I usually cut it into separate colours.
I stick the tape to the magnet sheet and cut along the edge with kitchen scissors. You can make the lengths whatever you wish, but I like 2"x6" (you can string as many as you want together to make bigger areas). White for the front (when you park), yellow for the side, and red for the back.
I also like to take the yellow ones and cut them into 1"x12" strips, which I will partially outline the vehicle with.
None of it is permanent, once you are off the road, just pull all your magnets off and stick them inside somewhere. When I'm at a show and don't want them on my cab interior walls, I stick them to the inside walls of a 40mm ammo can and put the lid on!
Cheers
PS - when I first came up with this idea, I tested it on the hood and sides of my POV. The magnets stayed in place at 80mph (yes, we have some high speed roads here!).