These small signs on the side of Maine roads have always made me curious to know what they mean. It turns out it's pretty straightforward, but only to those who need to know about them.

I've seen them on state routes throughout Maine. They're tiny, so if you blink you'll miss them, but they read "D.O.T. COMPACT - URBAN LINE."

Maine DOT via Facebook
Maine DOT via Facebook

My first thought was that Maine's DOT uses these signs to mark where higher population areas begin; places that are more urban than rural, hence the "urban line." But that didn't make a lot of sense. That's what town line signs are for.

So I've wondered for many years what they're all about, until I recently came across a post on Facebook from the Maine DOT that answered this many-years-long mystery for me.

It's really simple. These signs mark the spot where the responsibility of maintaining the road changes hands between the State of Maine and the local municipality. Things like plowing, road maintenance, and other road work all fall into the maintenance category. This sign marks the spots where DOT trucks can lift their plow blades because their work is done here, and the rest is up to the local municipality.

There was one question in the comments of the Facebook post asking "Does it also apply to discharge of firearms within a city limit?"

MaineDOT responded by saying, "Compact areas are set by DOT for highway maintenance purposes only. However, some towns have crafted local ordinances (like firearms) for themselves and use compact areas as their defined area."

Finally, my curiosity is no more. Cue the video:

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