FROST PHASE 4 — DESCRIPTIVE AUTHORITY SCREENING

Run from the Sites source checkout:
python scripts/build-frost-phase4.py
python tests/frost-phase4.test.py
python tests/frost-study.test.py

Dependencies: numpy, scipy. Exact versions used are in runtime.json.
The source checkout includes all verified inputs listed in source-register.json.
The download ZIP holds phase 4 outputs, code, tests and design; source data remain
in the unchanged v1 frost and parking v4 releases. It is not a standalone raw-data bundle.

A1–A10 describe fixed authority frost-mean quantiles (141 eligible authority
features). D1–D10 remain the original national LSOA quantiles. Do not equate them.
Default rates use 131 authorities eligible in all five years; available coverage
is a sensitivity. Counts and miles are summed before division. No local-mileage
allocation, fitted model, adjusted effect or predictive claim is introduced.

All 2025 descriptive frost associations are now inspected. Preserve the frozen
modelling rules and use a new untouched year for prospective confirmation.
The original LSOA and matched major-road completion gates remain open.
See completion-audit.json for all deviations from the agreed phase plan.
