Ways of simulating legibility


Wondering if anyone has any ideas or recommendations of ways to test the legibility of a typeface. Especially for signage typefaces, I've seen specimens that simulate the glow of headlights or the blur of long-distance reading. I suppose I'm wondering if there is a standard of performing such tests/displaying the results or if it's just a blur filter in Photoshop (if so which one would most accurately simulate long-distance?). Thanks for any help.