What-If Studio · Module 1 — Speed-Limit Corridor Delta

Relative scenario deltas under fixed, measured demand — exposure & kinetic-energy analysis, not a crash prediction. crashstats.com.au family POC.

Corridor

Length (km)

AADT (veh/day)

Current limit (km/h)

Proposed limit (km/h)

Speed response — mean-speed change per 1 km/h of limit change: Conflict types present on corridor

Head-on possible (undivided) Side impacts (intersections) Pedestrians / cyclists present Run-off-road (trees/poles)

Demand fixedDelta-onlyNo OD inference Method: Nilsson power model with Elvik-refined exponents (fatal 4.6, serious 3.6, all-injury 2.4, range shown vs classical 4/3/2); kinetic energy ∝ v²; Safe System survivable impact speeds (head-on 70, side 50, ped/cyclist 30, fixed-object 40 km/h). Mean-speed response default 0.5 × limit change (field-observed range 0.25–1.0).

Fatal-outcome index

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Serious-injury index

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Kinetic energy / vehicle

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at mean operating speed

Travel time cost

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Honesty box. This tool moves exposure and energy, not proven crash counts: converting these deltas into expected-casualty claims requires an EB/CMF evaluation design (separate, gated). Demand is measured or banded AADT taken as given — this platform family does not infer traffic volumes from models (that lane was tested and retired). Speed-response and exponents are user-visible assumptions; drag the slider to stress-test the conclusion.