Warning signs · W12-2
Low Clearance Advance sign
Archive file: W12-02 Low Clearance Advance/W12-02 Low Clearance Advance 30x30.svg
FHWA public-use information
What it means
An overhead obstruction ahead has the clearance shown.
Source: FHWA MUTCD — MUTCD 11th Edition with Revision 1 (December 2025), Section 2C.25, paragraph 01, PDF page 213.
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Meaning
Low Clearance Advance warns of limited room above your vehicle. Compare the displayed height with the height of what you are driving before reaching the structure. PennDOT says not to enter when the vehicle is taller than the posted clearance; hoping to fit is not a substitute for that comparison.
What to do
Know whether the structure can accommodate your vehicle and choose another path if it cannot. Pennsylvania identifies underpasses, tunnel entrances and parking garages as possible locations for this warning. The height restriction is relevant to more than bridges on open highways.
Where it is used
Federal guidance also places the warning with a distance panel at a nearby junction or a sufficiently wide place where an over-height vehicle can detour or turn around. Overhead signs may supplement it at the structure. Use the advance information while an alternative path is still available.
A sign to tell apart
Advisory Speed gives a recommended speed for a road condition. Low Clearance gives a height to compare with your vehicle. The numbers answer different questions: slowing down does not make an over-height vehicle fit through an opening that is too low.
Practice with explanations
These are original learning questions based on the cited handbooks. Read each answer and its explanation below.
1. Your vehicle is 13 feet tall. A Pennsylvania underpass is signed for 12 feet 6 inches of clearance. What should you do?
- Drive through slowly.
- Do not enter; the vehicle is too tall.
- Use the middle of the road without checking other restrictions.
Answer: B. Do not enter; the vehicle is too tall.
The vehicle is taller than the posted opening. Pennsylvania says not to enter in that situation.
2. Does Pennsylvania’s low-clearance guidance apply at a parking-garage entrance?
- No; it applies only to freeway bridges.
- Only if a police officer is present.
- Yes; a parking-garage entrance is one listed location.
Answer: C. Yes; a parking-garage entrance is one listed location.
The handbook lists garages and tunnels as well as underpasses. Compare vehicle height with the displayed clearance there too.
State source coverage
Handbook coverage and sample questions do not prove that a sign will appear on your exam. Even a published test scope cannot guarantee an individual exam question.
Pennsylvania
Handbook coverage
Pennsylvania’s driver manual explicitly discusses this sign. This establishes handbook coverage, without a promise about any individual exam.
Pennsylvania permit sources · Practice with Pennsylvania questions
State variations
State-specific variations have not been independently established for this study.
Verified question coverage
These free state-bank questions were independently verified. This does not establish complete state-bank readiness, app availability or what will appear on your permit exam.
No currently verified state-bank question is available for this sign.
The linked 20-question permit quizzes do not currently include this sign.
This meaning is a federal MUTCD reference. Check your state's handbook for its rules and sign coverage; this page does not establish what appears on a state permit exam.
Try the free road sign quiz or find your state's handbook.
