Signal Warrants (MUTCD Ch. 4C)

Chapter 4C, Traffic Control Signal Needs Studies, in MUTCD Part 4 (11th Edition). Nine warrants define the minimum conditions under which a signal might be justified. Your job in a warrant study: collect the right data per warrant, plot/compare against the tables and figures, and document engineering judgment.

The nine warrants and the data each needs

1. Warrant 1 — Eight-Hour Vehicular Volume: 8 hours of major-street (both approaches) + higher-minor-approach counts vs Table 4C-1 (Condition A: minimum volume; Condition B: interruption of continuous traffic). One warrant — meet A or B and you’re done. 70% columns allowed if major-street speed > 40 mph or isolated community < 10,000.
2. Warrant 2 — Four-Hour Vehicular Volume: any 4 hours of an average day; plot major total vs critical minor on Figure 4C-1 (4C-2 for the 70% factor).
3. Warrant 3 — Peak Hour: 1 hour, unusual cases only — office complexes, plants, industrial sites that dump large volumes over a short time. Figure 4C-3/4C-4 (plus a delay/volume condition set). If it’s the only warrant met, the signal should be traffic-actuated.
4. Warrant 4 — Pedestrian Volume: simultaneous major-street veh/hr AND peds/hr crossing the major street — any 4 hours (Fig 4C-5) or one peak hour (Fig 4C-6); 70% figures if > 35 mph or isolated small community. Not applicable within 300 ft of the nearest signal or STOP controlling the crossed street (unless progression isn’t hurt). Met → ped signal heads required.
5. Warrant 5 — School Crossing: a gap study, not a volume plot — adequate gaps fewer than minutes in the crossing period, AND a minimum of 20 schoolchildren during the highest crossing hour. Consider guards, flashers, and grade separation first. Same 300-ft adjacency limit as Warrant 4.
6. Warrant 6 — Coordinated Signal System: platooning need — adjacent signals too far apart to keep platoons intact (one-way, or two-way where the new signal completes progressive operation). Don’t apply if resulting spacing < 1,000 ft.
7. Warrant 7 — Crash Experience: angle + pedestrian crash counts vs Table 4C-2 (1-year) or 4C-3 (3-year, by severity and lane configuration), AND a documented failed trial of alternatives, AND volumes ≥ 80% of Warrant 1 (8 hours) or 80% of Warrant 4. Needs crash reports (type, severity), not just a summary count.
8. Warrant 8 — Roadway Network: common intersection of two major routes — ≥ 1,000 vph total entering in a weekday peak hour with 5-year projections meeting Warrant 1, 2, or 3, OR ≥ 1,000 vph for any 5 hours of a Saturday/Sunday. Needs forecast volumes, not just counts.
9. Warrant 9 — Intersection Near a Grade Crossing: use only when no other warrant is met — track centerline within 140 ft of the stop/yield line on a STOP/YIELD approach; plot the highest rail-traffic-hour volumes on Figure 4C-9/4C-10 (adjusted by clear storage distance D). Try geometric/control alternatives first.

Counting rules that trip people up

Any four consecutive 15-minute periods may count as 1 hour (no overlapping) · bicyclists count as vehicles or pedestrians depending on where they ride · minor-street right turns may be partially subtracted by engineering judgment · a wide-median intersection may be analyzed as one intersection or two.

Meeting a warrant ≠ getting a signal

Section 4C.01 (Standard): “The satisfaction of a traffic signal warrant or warrants shall not in itself require the installation of a traffic control signal.” A warrant is one input to an engineering study — signals can increase some crash types vs STOP control, so Chapter 4B pushes you to consider alternatives (revised geometry, roundabouts, restricted movements) even where a warrant is met. Conversely, an agency may install where no warrant is met if an engineering study documents why. On Florida projects the alternatives question is formalized — see Intersection Control Evaluation (ICE).

Warning

Never quote warrant thresholds (Table 4C-1 volumes, figure curves, the 20-schoolchildren and 140-ft values) from memory or from the 2009 edition — read them from the current MUTCD 11th Edition, Revision 1 (Dec 2025) PDF for the analysis year, and check FDOT TEM supplements. The one-liners above are from the Dec 2023 11th-Edition Part 4 text #status/verify against Revision 1.

Tip

Free Part 4 PDF, the 2009→11th redline, and recorded FHWA webinars all live on the MUTCD 11th Edition page (link above) — the redline is the fastest way to see what changed in the warrants.

See also: Intersection Control Evaluation (ICE) · MUTCD · How to Read a Signal Timing Sheet