Exit number plaque

How to read it

The MUTCD requires exit numbers on every freeway interchange, on a plaque (E1-5P) at the top of the advance guide and exit direction signs. The plaque sits at the top right for an exit on the right. For a left exit it sits at the top left with the word LEFT in black on a yellow panel, because drivers might not expect an exit on that side. Pennsylvania's manual teaches the same reading: a plaque on the left side of the sign means the exit is on the left of the highway. This page describes the national standard; it isn’t legal advice, and each state applies it on its own roads.

Also searched as: exit numbers, exit sign highway, highway exit sign.

Mileage-based, not sequential

Exit numbers follow the mile markers. The MUTCD requires the reference location (mileage) method and forbids the consecutive method that numbers exits 1, 2, 3 in order. It gives two reasons: drivers can work out distances, and new interchanges don't force the whole route to be renumbered. Numbering starts at the southern or western end of the route within each state, even when the road comes in from a neighbouring state. Pennsylvania's manual says its exits were renumbered to match the mile markers, so the distance between Exit 95 and Exit 20 is 75 miles, and Florida's says its Interstate mile markers match the exit numbers.

Letters after the number

Where more than one exit belongs to the same mile point they share a number with suffix letters, EXIT 25 A, EXIT 25 B, lettered from A in the direction the numbers increase. The MUTCD doesn't allow both EXIT 256 and EXIT 256 A on the same route in the same direction. Exit numbers don't carry compass letters for the cross road. The 11th edition (2023) adds worked examples: a crossroad between mile 15 and mile 16 is EXIT 15.