Regulatory signs · R3-5a
Through Only sign
Archive file: R03-05a Mandatory Movement Lane Control - Through Only/R03-05a Mandatory Movement Lane Control - Through Only 30x36.svg
FHWA public-use information
What it means
This lane must continue straight through the junction.
Source: FHWA MUTCD — MUTCD 11th Edition with Revision 1 (December 2025), Section 2B.28, paragraph 08, PDF page 134.
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Meaning
Through Only assigns straight-ahead travel to one lane at the intersection. The arrow describes the required path from that lane, not permission to turn once you find a traffic gap. The federal manual treats this as a mandatory movement with ONLY on the panel.
What to do
Pennsylvania tells you to continue straight if you reach the junction in a through lane even though you intended to turn. A lane assignment also does not require entering a blocked intersection: if traffic prevents you from clearing it, wait even with a green light. Follow the lane’s path once movement is safe.
Where it is used
The federal symbol is mounted overhead above the lane it governs. Compare your position with that panel before entering the junction; another lane may have a turning assignment. Reading the lane and the signal together avoids treating a green light as permission to leave the assigned path.
- Official source · MUTCD 11th Edition with Revision 1, Section 2B.28, paragraphs 01–02 · PDF page 133 · Checked
- Official source · MUTCD 11th Edition with Revision 1, Section 2B.28, paragraph 02 · PDF page 133 · Checked
- PA-en · Chapter 3 — Approaching intersections — Through traffic lane · PDF page 52 · Checked
A sign to tell apart
Mandatory Turn also uses ONLY, but its arrow requires a turn. Through Only requires continuing straight. Read the arrow’s path, not just the shared word, and keep the required movement for your lane separate from whether the signal currently allows you to enter.
Practice with explanations
These are original learning questions based on the cited handbooks. Read each answer and its explanation below.
1. You want to turn, but reach a Pennsylvania intersection in a lane marked for through traffic. What does the handbook require?
- Turn if you can signal quickly enough.
- Continue straight through.
- Use either direction because the light is green.
Answer: B. Continue straight through.
A through-lane assignment still controls when your planned route called for a turn.
2. The light is green for your Pennsylvania through lane, but vehicles block your path across the intersection. What should you do?
- Enter and wait in the intersection.
- Change your assigned movement to get around them.
- Wait until you can clear the intersection.
Answer: C. Wait until you can clear the intersection.
The through assignment does not override the need for space beyond the junction. Wait even on green when the path is blocked.
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.
No state test-scope claim is independently approved for this study.
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.
