Railroad advance warning sign
A round yellow sign with a black X and the letters R R. It warns of a railroad crossing ahead.
Easily confused with
How to read it
It is the only round sign in the MUTCD's table of shapes, and the Manual requires it on every road ahead of a highway-rail crossing, with a few exceptions. It stays yellow even in work zones, where other warning signs turn orange. Pennsylvania's manual says it is placed far enough ahead to allow a stop before the tracks; the crossbuck marks the crossing itself.
Rules vary by state and country. This explains the sign's standard meaning in the U.S. Manual on Uniform Traffic Control Devices; it isn't legal advice.
Read next
- Next in Road signsPlayground signA diamond with a child on a slide. It warns of a children’s playground beside the road.
- The same shape in Greek lettersQuantum circuit gate symbols (H, X, CNOT, measurement)The symbols of a quantum circuit diagram: each horizontal line is a qubit, a box with a letter is a gate (H for Hadamard, X, Y, Z, S, T), a dot joined by a line to ⊕ is a controlled-NOT, and a box with a meter is a measurement.
More road signs
The same shape elsewhere
Browse symbols drawn with circles, crosses or letters and numbers.
Sources
- MUTCD 2009 Edition, Chapter 8B: Signs and Markings (Railroad and Light Rail Transit Grade Crossings), MUTCD 2009, Part 8, U.S. Federal Highway Administration, Section 8B.06
- MUTCD 2009 Edition, Chapter 2A: General, MUTCD 2009, Part 2, U.S. Federal Highway Administration, Section 2A.09, Table 2A-4
- MUTCD 2009 Edition, Chapter 6F: Temporary Traffic Control Zone Devices, MUTCD 2009, Part 6, U.S. Federal Highway Administration, Section 6F.16
- Pennsylvania Driver's Manual, Chapter 2: Signals, Signs and Pavement Markings, Pennsylvania Department of Transportation, p. 16
- California Driver's Handbook, Section 7: Laws and Rules of the Road, California Department of Motor Vehicles, Signs
- The Evolution of MUTCD, Updated December 2023; after H. Gene Hawkins, Jr., ITE Journal, 1991–1994, U.S. Federal Highway Administration, Prologue
Researched, edited and approved by Rory Hansen before publishing. Last reviewed October 2, 2026. How we research
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