Did You Know How Mile Markers On The Highway System Are Established?

Posted by on Nov 27, 2018

By: Mark Randall, PE (TN), CPESC

You may know that mile markers or mile posts tell drivers their location along an interstate or highway, but did you know how those markers are established or the other functions that they serve?

Mile markers are used to indicate the distance traveled within a state as well as the distance to a destination such as a city or town.  The mileage begins at the state line and increases from south to north for north-south highways and from west to east for east-west highways.  This system not only designates the distance of travel, it also indicates the direction of travel.  Increasing mileage reflects northerly or easterly travel, and decreasing mileage reflects southerly or westerly travel.  Sometimes the distance to a destination, such as a city, is measured to a zero mile marker and mileage is measured to that point.  The image below is of the zero mile marker in Memphis, TN.

Mile markers in most states also help drivers to anticipate the distance to their desired exit.  Exits in these states are numbered according to mileage, so exit 5 would occur near mile 5.  Markers also aid emergency personnel when responding to emergencies by providing a reference point that is close to an accident or point of need.

When you are traveling this holiday season, give some attention to these helpful traveler’s aids and remember mile markers are more than just numbers along a route.  They can help you know your direction of travel, your location along a route, and the distance to your next exit or destination.  And if you encounter trouble along the way, a mile marker can help emergency personnel find you.

 

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