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Home / MUTCD / Warning Signs

MUTCD Warning Signs — Curves, Chevrons & Advance Placement

Warning signs — the yellow diamonds — are Chapter 2C of the MUTCD, 11th Edition. Selection is driven by the difference between the posted speed and the curve advisory speed, and placement by how much distance a driver needs to react.

RequirementMUTCD 11th Ed. StandardSection
Basis for useEngineering study or engineering judgment — unneeded warning signs breed disrespect for all signs§2C.01
Curve vs. Turn signsCurve (W1-2) is the default horizontal alignment sign; Turn (W1-1) where the advisory speed is 30 mph or less§2C.07
When alignment signs are requiredPer Table 2C-4, based on speed differential, AADT, and roadway type§2C.06
Chevrons (W1-8)Spacing per Table 2C-5 by advisory speed and radius — roughly 40 ft at ≤15 mph up to 200 ft above 60 mph§2C.08
Advisory speed plaque (W13-1P)Shows the recommended curve speed in 5 mph increments, mounted below the warning sign§2C.59
Advance placementPer Table 2C-3 — from about 100 ft at low speeds to 1,600 ft where drivers must slow or change lanes at high speedTable 2C-3

Worth knowing

  • Advisory speeds are set by an engineering study (ball-bank indicator or accelerometer method) — not by guessing.
  • Warning signs use black on yellow; fluorescent yellow-green is reserved for pedestrian, bicycle, and school signs.
  • Doubling up (signs on both left and right) is an option for emphasis on multi-lane and divided roadways.
  • Temporary (orange) versions of most warning signs exist for work zones under Part 6.
Source: Manual on Uniform Traffic Control Devices, 11th Edition (Federal Highway Administration, December 2023, public domain) — read the full manual at mutcd.fhwa.dot.gov. Your state may still be operating under the 2009 edition or a state supplement — for state construction specs, see the DOT specifications library.
Sign Placement →Regulatory Signs →Work Zones →