Railroad crossing signs
Exempt Crossing sign
Mounted below a crossbuck or stop sign, this plaque tells certain vehicles, such as school buses or hazardous material carriers, that the law requiring them to stop at every railroad crossing does not apply here.
- Wide rectangle
- White
- MUTCD R15-3P
Shape and background first
Federal designation R15-3P in the MUTCD, the national standard every state signs to. Posted at lower risk crossings, often ones with gates or very light rail traffic, where forcing every bus and truck to stop would add little safety benefit.
What the MUTCD specifies
Designation: R15-3P
MUTCD Section 8B.11
Conventional road size: 24 x 12 in
Option: An EXEMPT plaque may be placed below a Crossbuck only where law or regulation authorizes that designation.
Source: Federal Highway Administration, MUTCD 11th Edition (December 2023), Part 8, Table 8B-1; Section 8B.11, verified 2026-09-26.
What the test wants you to know
The mistake people make
An ordinary driver was never required to stop at a crossbuck unless a train is actually coming, so this plaque is not really about you, it is about vehicle classes with a stricter default rule. Test questions on this sign are usually checking whether you know which vehicles that mandatory stop law targets in the first place.
The sign people confuse it with
Exempt Crossing gets mixed up with Crossbuck more than any other pairing in this category. Put them side by side and the difference is obvious, which is exactly why it is worth doing once rather than meeting them cold in the exam.
Exempt Crossing
Mounted below a crossbuck or stop sign, this plaque tells certain vehicles, such as school buses or hazardous material carriers, that the law requiring them to stop at every railroad crossing does not apply here.
Crossbuck
Marks the railroad crossing itself.
