int_stint_geometry

Foundation for all downstream window functions.

Part of the Physics family.

Foundation for all downstream window functions. One row per race lap (the FULL chronological sequence, including SC/VSC/pit/invalid laps) so physics-layer LAG/EWMA windows decay correctly across those gaps instead of treating the lap before/after a gap as adjacent. Builds stint identifiers (stint_id), lap positions within stints (lap_in_stint = chronological ordinal, valid_lap_in_stint = ordinal among valid laps only, age_in_stint = tyre_life), and compound tracking. Consumers that fit pace/regression models filter to is_valid_lap (or key off valid_lap_in_stint) at their own input boundary. All Layer 03 window functions partition on stint_id.

Lineage

Overview

Property	Value
Layer	intermediate
Family	Physics
Contract enforced	No
Upstream	stg_laps, stg_tyre_allocations

16 tests guard this model - 11 generic, 5 singular.

Columns

Column	Type	Nullable	Tests	Description
stint_id		Yes	not_null	Surrogate key combining race_year, race_id, driver_id, stint_number
lap_id		Yes	not_null, unique	Foreign key to stg_laps
lap_in_stint		Yes	not_null	Chronological ordinal within the stint (1, 2, 3, …), counting every lap including SC/VSC/pit/invalid ones.
valid_lap_in_stint		Yes		Ordinal among valid laps only within the stint (NULL on invalid laps). Use for pace-fitting position/length logic instead of lap_in_stint.
stint_length_actual		Yes	not_null	Total lap count in the stint (valid + invalid).
stint_length_valid		Yes		Count of valid laps in the stint.
is_valid_lap		Yes	not_null	Carried through from stg_laps. Timed, on-track, not deleted, accurate, not lap 1, no SC/VSC.
is_pit_lap		Yes	not_null	Carried through from stg_laps. TRUE for the out-lap/in-lap of a pit stop.
is_safety_car_lap		Yes	not_null	Carried through from stg_laps. TRUE when the TrackStatus string contains a 4 (full SC).
is_vsc_lap		Yes	not_null	Carried through from stg_laps. TRUE when the TrackStatus string contains a 6 or 7 (VSC).
is_red_flag_lap		Yes	not_null	Carried through from stg_laps. TRUE when the TrackStatus string contains a 5 (red flag).
age_in_stint		Yes	expect_column_values_to_be_between	Tyre age in laps at this lap. Directly from FastF1 TyreLife (no imputation, no reconstruction). 343 rows (0.21%) carry NULL: 325 of them (94.8%) sit on lap 1 of a stint, where tyre-life occasionally arrives without a reading. This is a pattern, not random scatter, and occurs at the exact position where starting_tyre_age_laps is derived. For stints opening on lap 1: if age_in_stint is NULL at the stint start and you need a starting age, the column is missing; do not assume the tyre is fresh (a used/scrubbed set starting a stint will have age_in_stint > 1 or NULL, but never 0). Consumers should carry this column forward or declare how NULLs are handled.
compound_code		Yes		Tyre compound code (C1–C5) assigned by Pirelli for this race, joined from stg_tyre_allocations on (race_year, circuit_key, compound_label). Absolute identifier, unlike compound_in_stint which is relative. Enables cross-circuit compound comparison and physical-parameters lookup in dim_compounds_season. PROVISOS: (1) Data starts at 2019-01-20 (first Pirelli 2019 season race). 2018 rows carry NULL by construction — Pirelli’s relative naming began in 2019, and 08d’s sourcing covers 2019-2024 only. (2) Sourced from user verification (2026-09-17) of a 128-row Pirelli allocation table covering 127 mart races 2019–2024 (100% join coverage). Sourcing caveat: only 47 of 128 source URLs resolve; see _improvements/work/08-foundations-repair.md (08d) for the full provenance and epistemics ruling.
compound_label		Yes		Tyre compound label (hard, medium, soft) assigned by Pirelli for this race. Relative to the circuit - Pirelli picks 3 compounds per weekend and calls them hard/medium/soft, so “soft” at one circuit is not the same rubber as “soft” at another. The compound_code is the absolute identifier; this label is the relative one.
race_year		Yes		Season year.
race_id		Yes		Race identifier.
driver_id		Yes		FastF1 three-letter driver code (e.g. VER, HAM).