The Secret Formula to Metro Detroit’s North/South Address System

Do the Math
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In the dark ages before iPhones and Siri were there to guide you, there was math.

The way most metro Detroit addresses are assigned on north/south roads, a relatively simple formula can approximate where a location is in relation to a mile road. (We don’t know why. Or who discovered it. It just works.)

The secret formula? Minus 5, divide by 2.

Say you’re invited to a graduation at the International Academy of Macomb at 42755 Romeo Plank Rd.

Take the first two numbers of the address (42) and subtract 5. That equals 37. Now divide 37 by 2. Your magic number is 18.5, which means the school is at approximately 18 1⁄2 Mile Road on Romeo Plank.

Pretty cool, right? Now that you know, just forget about it and let Siri do the work.

Learn more about Michigan’s mile roads in our “Mile by Mile” City Guide in this month’s issue of Hour Detroit.