Highway basics

Left exit vs right exit: what the exit tab tells you

That little "EXIT" tab on top of a green highway sign does more than number the exit — which side it sits on tells you whether you'll leave from the left lane or the right. Here's how to read it.

The exit tab

The small tab mounted on top of a big green guide sign carries the exit number. It's called the exit tab, and where it sits on the sign is a deliberate signal set by the federal sign manual (the MUTCD) — not just decoration.

Right side = right exit

By default the exit tab sits on the right of the sign, and the great majority of exits leave from the right lane. If the tab is on the right or centered, plan to be in the right-hand lanes to take the ramp.

Left side = left exit

When the tab is placed on the left of the sign — often with the words "LEFT EXIT" — the ramp leaves from the left lane instead. Left exits are less common and easy to miss, which is exactly why the tab moves to the left to warn you to get over early.

The number is usually your mile marker

The number on the tab is usually the exit's mile marker, so it also tells you how far along the highway you are. For your continuous position between exits, watch the small green mile markers — or let MileCheck read your exact mile marker in real time as you drive. Mile markers vs exit numbers →

Know exactly where you are — live

MileCheck shows your nearest mile marker in real time as you drive, plus live DOT alerts and the nearest camera on your route. Free to start, works offline, runs on CarPlay and Android Auto.

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Questions, answered

What does the exit tab on a highway sign mean?

It shows the exit number, and its position signals the exit side. A tab on the right (the default) means a right-lane exit; a tab on the left means the ramp leaves from the left lane.

How do I know if an exit is on the left?

Look at the exit tab on the sign. If it's placed on the left side, often labeled "LEFT EXIT," the ramp leaves from the left lane. A right or centered tab means a normal right-side exit.

Why are some highway exits on the left?

Left exits usually come from the road's design — older interchanges, express/local lane splits, or geography. Because drivers expect right exits, signs move the exit tab to the left to warn them in advance.

Is the exit number the same as the mile marker?

On most US interstates, yes — exit numbers are mile-based, so the number on the tab is about the same as the nearest mile marker. Some older highways use sequential numbering that doesn't match mileage.