Florida-specific reference
Florida reconstruction conventions, roadway and traffic-engineering references, evidence practices, and worked case context for investigators using CrashCompute.
Florida's Advanced Traffic Crash Reconstruction course materials use familiar reconstruction relationships for critical-speed yaw, roadway banking, momentum, airborne motion, and related analyses. CrashCompute identifies where a Florida convention differs only by rounding or notation.
FDOT manuals are useful for evaluating roadway design, sight distance, cross slope, superelevation, traffic studies, signs, signals, markings, and operational context. Design values should not replace measured crash-scene values when case-specific measurements are available.
Florida / FPSI / FHP
| Topic | Florida convention or notation | CrashCompute treatment |
|---|---|---|
| Time-distance | D = 1.466 × S × t Feet, mph, seconds, using the traditional reconstruction rounding shown in Rivers. The exact unit conversion is approximately 1.4667 ft/s per mph. | Perception-Reaction Distance and related time-distance worksheets retain the traditional 1.466 reconstruction constant. |
| Yaw radius | R = C²/(8M) + M/2 Radius from chord length and middle ordinate. | Radius from Chord & Middle Ordinate. |
| Critical-speed yaw | S = 3.86 × √(R × f) The 3.86 coefficient is the conventional U.S.-customary Florida training form for the basic relationship. Banking and superelevation require the appropriate adjusted relationship. | Critical Speed from Yaw Mark also shows the algebraically equivalent √(15Rf) form and now reports the Florida/FPSI convention as a cross-check. |
| Center-of-mass radius | RCOM = Rtire path − T/2 When the measured radius follows a tire path rather than the vehicle center-of-mass path, apply a supported track-width correction consistent with the mark and vehicle geometry. | The critical-speed worksheet accepts an optional track width and shows the corrected COM radius used in the calculation. |
| Two-dimensional momentum | Σ(WV)x,before = Σ(WV)x,after Σ(WV)y,before = Σ(WV)y,after Florida training examples commonly use vehicle weights, approach/departure speeds, and approach/departure angles. The gravitational conversion cancels when weights are used consistently. | Momentum, 360 Degree solves the same two component equations and preserves the Florida-style W₁/W₂ and S₁-S₄ notation. |
| Coefficient of restitution | e = relative separation speed / relative approach speed | Restitution & Delta-V uses the generalized relative-speed form rather than assuming a particular impact orientation. |
For higher superelevation and other non-basic conditions, use the full relationship taught in the applicable Florida course material and document the source edition. CrashCompute's Critical Speed with Grade & Crown worksheet is intended for those cases.
Florida Department of Transportation
Applies the 2026 MUTS design-equation method and records ball-bank or accelerometer study context, including the minimum run count. It is roadway engineering guidance, not a reconstruction of vehicle speed.
Compares measured available sight distance with the current 2026 FDM Table 210.11.1 value selected by design speed, grade, and direction.
Compares a measured curve radius with the applicable 2026 FDM Table 210.8.2 design family without treating the design value as a scene measurement or actual vehicle speed.
Compares field-measured pavement cross slope with selected current FDOT standard and RRR ranges while retaining the field measurement as the controlling case evidence.
Current Florida design criteria and processes. Useful for roadway geometry, stopping sight distance, horizontal and vertical alignment, cross slope, and superelevation context.
The 2026 MUTS, effective January 1, 2026, provides FDOT's minimum standards for traffic engineering studies on Department roads and recommended guidance for local agencies. It covers speed, travel-time, advisory-speed, and related studies.
Florida standards and guidelines for the State Highway System, including signs, signals, markings, and specialized operational topics.
FDOT's traffic-services library links the Speed Zoning Manual, MUTCD, MUTS, TEM, and related operational guidance.
FDOT design guidance calls for evaluating wet-crash history, pavement condition, roadway geometry, water-film evidence, and related drainage factors when hydroplaning is a concern. CrashCompute separates a pressure-based theoretical screening threshold from an advanced evidence checklist. It does not reproduce or substitute for FDOT's official Hydroplaning Prediction Tool.
FHWA evidence and validation
FHWA's Crash Investigation and Reconstruction Technologies and Best Practices identifies tire marks, vehicle and body positions, pavement marks, debris, roadway grade, and environmental evidence among the scene data needed for reconstruction. It also emphasizes that computer-generated reconstruction results should be verified and defensible.
Record how the value was obtained: tape, measuring wheel, total station, GNSS/RTK, laser scanner, photogrammetry, EDR, video, or another documented method.
Preserve the equation, units, assumptions, software version, sensitivity, and an independent check where the result is material to the reconstruction.
Florida worked example
A 2021 University of South Florida mathematical-modeling paper, developed from a Florida Highway Patrol traffic-homicide case, applies conservation of linear momentum using vehicle weights, pre- and post-collision directions, and post-collision speeds. The paper reports hand-calculated impact speeds of approximately 40.85 mph and 21.96 mph, compared with reconstruction-software results of approximately 40.97 mph and 22.35 mph.
The paper's most useful practical lesson is not the small numerical difference. It is the sensitivity to approach and departure angles. The authors specifically recommend repeated angle measurements because angular error can materially change a two-dimensional momentum solution.
Primary and supporting sources
CrashCompute is independent of FDOT, FDLE, FPSI, FHP, FHWA, USF, and the cited publishers. Listing a source identifies provenance or supporting context and does not imply endorsement.