What: the free national signal-timing library, four items deep. NCHRP Report 812 — Signal Timing Manual, Second Edition (STM2), free PDF from National Academies Press (link above): phasing, cycle/split/offset development, coordination, preemption/priority, oversaturated and adaptive strategies — the source document behind nearly every planned note on this shelf (NEMA phasing, offsets, TOD plans, FYA). Plus: FDOT Traffic Signal 101/102 CBTs and signal-timing/performance-measure trainings at fdot.gov/traffic/training (some carry PDHs); the FHWA Signalized Intersections Informational Guide, 2nd Ed (FHWA-SA-13-027), free PDF — safety, geometric design, and operations from low-cost timing/signing fixes up to reconstruction, with multimodal treatments; and UDOT’s open-source ATSPM codebase at github.com/udotdevelopment/ATSPM (live public example: udottraffic.utah.gov/atspm).
Why: everything here is free and citable — STM2 for how timing values are developed (not just what the sheet says), the FHWA guide for justifying head placement/ped features/intersection treatments in review comments, FDOT CBTs for Florida-specific conventions, ATSPM because it’s where signal ops is going.
When: a timing sheet field confuses you → STM2 chapter on that topic before asking. Writing a plan-review comment on a signalized intersection → FHWA-SA-13-027. First month touching FDOT signals → Signal 101, then 102. Handed high-resolution controller data → ATSPM.
What ATSPMs tell you: automated performance measures from high-resolution controller logs — Purdue coordination diagrams (arrivals on green vs red → is the offset actually working?), split failures (phase maxed out with demand left → splits wrong), arrivals on green, ped delay, detector health. They replace “drive the corridor and feel it” with evidence, and the UDOT repo doubles as an automation/code study project.
Tip
STM2 and other NCHRP reports download free from nap.nationalacademies.org (free account) — never pay for NCHRP. The FDOT training page also hosts recorded TEM symposiums and the MUTS course.
Warning
STM2 is national guidance; FDOT/maintaining-agency policy governs actual timing values in Florida — use STM2 to understand, the agency table to comply. URLs and training catalog contents rot
#status/verify links and CBT list.
See also: How to Read a Signal Timing Sheet · Clearance Intervals and Ped Timing · Signal Warrants (MUTCD Ch 4C)