I hope this is the right forum but saw this yesterday. Thought that it should be shared on AA too
https://www.3m.com/3M/en_US/particles/all-articles/article-detail/~road-traffic-safety-reflective-signs-visibility/?storyid=2cb8314f-358f-4924-800e-cc2b75191237&utm_campaign=rch_particle37&utm_medium=psm&utm_source=fb&utm_term=sgbg-tsd-na-en_us-rch-particle37-psm-fb-na-na-na-jun18