Is there a reason why directional, and mileage street signs are green?
I recall from Driver’s Ed years ago that all road signs are color coded. The Illinois Rules of the Road has a section helpfully titled colors of signs. There, it says that information, destination, and distance signs are always green. Sadly, it doesn’t say why.
Much appreciated.
To expand a little: these signs are green because the other colors are inappropriate.
Red is what you might call a “high priority” color – stop signs and yield signs, nothing else.
Yellow is the “warning color”; it’s used for just about every other highway warning sign there is (merging, falling rocks, speed bumps, etc.). Orange is for construction signs (and their equipment and their safety vests), and green – the “go” color – is for destination and distance signs. Brown and blue are used for certain destinations, but I believe it varies by jurisdiction. White is almost always for speed limits but there are a handful of informational signs – begin freeway, $1000 fine for littering, etc. – that are also white.
White signs are regulations; yellow signs are warnings. I was taught that you don’t have to obey a yellow speed limit sign - a yellow “25 MPH” sign before a curve means “Careful, you should probably slow down to 25”, not “You must slow down to 25 or you’ll get a ticket.”
Blue is usually for services (hospitals, restaurants, gas stations, rest stops) and brown is usually for parks.
Green, like traffic lights, is for go, hence directional signs.
Yellow (amber) is a warning, hence “Falling rocks”, “Kangaroos crossing”, “If you drive around this curve faster than 45 kph you have a high probability of crashing”.
Red is for danger, hence “Stop”, “Give way” and “No faster than 100 kph”.
Orange is halfway between red and yellow, hence “People working on the road” and “Accident ahead”.
Blue is information, hence tourist information centres, parking buildings and points of interest.