Bike Hack: The Little Green Signs

A “little green sign” for Route 23

Source: By Fwgoebel – Own work, CC BY 3.0,

Have you ever been driving (or biking) along somewhere in New York State and wondered about the little green signs that you keep seeing over and over on the side of the road? These little signs are actually reference markers put up by the NYS Department of Transportation after the Highway Safety Act of 1966 required that “each state shall have a highway safety program….(that) shall include, but not be limited to, provisions for….surveillance of traffic for detection and correction of high or potentially high accident locations”.

In short, in a pre-computer and pre-GPS world, each state needed to figure out their own way to reference every segment of state-owned roadway for traffic, maintenance and crash reporting purposes.

And, of course, New York State being what it is, came up with an ingeniously confusing, complicated, yet workable solution, which culminated in these little green signs that show an almost nonsensical jumble of numbers and letters.

But these signs are a great resource if you are ever lost on your bike and you need to figure out what road you are on. The top row of these signs is (almost) always the route number for the state road on which you are traveling. So in the absence of other signage, these little green markers can at least help you figure out what road you are on. On most 2 lane roads, they are every 0.2 mile, so you don’t have to bike far to figure it out. If you are riding on a 4-lane road, you’ll see them every 0.1 mile.

If you are interested in the real nitty-gritty about how these little green signs work, check out the NYSDOT Reference Marker Manual. It’s fascinating. It will make you appreciate the lengths that people had to go to to code highway segments before computers and GPS could just assign everything a coordinate.

And keep in mind, you will only see these signs in New York State. Other states have their own signs, which may or may not make sense.