Xref: utzoo comp.cog-eng:633 comp.software-eng:813 Path: utzoo!attcan!uunet!seismo!sundc!pitstop!sun!decwrl!labrea!rutgers!cmcl2!adm!smoke!geoffs From: geoffs@smoke.ARPA (Geoffrey Sauerborn ) Newsgroups: comp.cog-eng,comp.software-eng Subject: Re: OPEN LOOK Message-ID: <8501@smoke.ARPA> Date: 15 Sep 88 13:25:10 GMT References: <7099@well.UUCP> Reply-To: geoffs@brl.arpa (Geoffrey Sauerborn (TANK) ) Organization: Ballistic Research Lab (BRL), APG, MD. Lines: 31 In article josh@klaatu.rutgers.edu (J Storrs Hall) writes: > >Personally, I think that traffic lights should be ... ...(BLUE , RED )... The fact that tail lights are red and headlights are white is not a random event. There has actually been a lot of thought put into it. RED is safer than BLUE for stops since it can be seen more easily. (But White is even better than RED for that reason - but that is why it is used for headlights). Physics will tell you that blue (a higher energy frequency) will travel further than red. But a fact of human engineering is that red is more easily noticed by the eye - especially when other light (sun light) is interfering. This is why many police vehicle use BOTH red and blue. Red for Day, Blue for Night. Next time you see a police flashing its lights in the extream distance, you'll see likely notice just the red at first. -- ---> geoffs@brl.arpa -or- geoffs@smoke.brl.mil -- -- ---> geoffs@brl.arpa -or- geoffs@smoke.brl.mil --