> ## Documentation Index > Fetch the complete documentation index at: https://offthepace.mintlify.site/llms.txt > Use this file to discover all available pages before exploring further. # fct_ghost_car_pace > One row per (ego_driver, host_constructor, race, lap). Part of the [Marts](/transform/families/marts) family. One row per (ego\_driver, host\_constructor, race, lap). "What if" lap times: recombines ego driver's skill (residual) with host constructor's car pace. predicted\_lap\_time\_s = ego skill + host car. Degenerate check: ego == host → predicted == actual. Powers "ghost car" simulator: replay with different cars. ## Lineage ```mermaid theme={null} flowchart LR int_circuit_x_constructor_interaction --> fct_ghost_car_pace int_compound_cliff_predicted --> fct_ghost_car_pace int_constructor_deg_sensitivity --> fct_ghost_car_pace int_constructor_structural_pace --> fct_ghost_car_pace int_lap_residual_decomposed --> fct_ghost_car_pace stg_laps --> fct_ghost_car_pace fct_ghost_car_pace --> fct_ghost_race_finish style fct_ghost_car_pace fill:#e40404,stroke:#e40404,color:#fff ``` ## Overview | Property | Value | | ----------------- | ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | | Layer | `marts` | | Family | [Marts](/transform/families/marts) | | Contract enforced | No | | Tags | `simulation`, `ghost_car` | | Upstream | [`int_lap_residual_decomposed`](../int/int_lap_residual_decomposed), [`int_compound_cliff_predicted`](../int/int_compound_cliff_predicted), [`stg_laps`](../stg/stg_laps), [`int_constructor_structural_pace`](../int/int_constructor_structural_pace), [`int_circuit_x_constructor_interaction`](../int/int_circuit_x_constructor_interaction), [`int_constructor_deg_sensitivity`](../int/int_constructor_deg_sensitivity) | **25 tests** [guard](/transform/ci/overview) this model - 23 generic, 2 singular. ## Columns | Column | Type | Nullable | Tests | Description | | ----------------------------- | ---- | -------- | -------------------------------------------------------------------------------------------------------------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------ | | `ghost_id` | | Yes | [`not_null`](/transform/ci/structural), [`unique`](/transform/ci/structural) | Surrogate PK = MD5(ego\_driver\_id \|\| host\_constructor\_id \|\| race\_id \|\| lap\_number) | | `predicted_lap_time_s` | | Yes | [`not_null`](/transform/ci/structural) | Recombined lap time using ego skill + host constructor pace. | | `actual_lap_time_s` | | Yes | [`not_null`](/transform/ci/structural) | Observed actual lap time for the ego driver. | | `predicted_residual_pace_s` | | Yes | [`not_null`](/transform/ci/structural) | predicted\_lap\_time\_s with the fuel-burn component backed out (the fuel term is simply omitted from the recombination sum). Fuel-adjusted so ranking by pace isn't biased by which lap window (heavy vs. light fuel) a driver ran. | | `actual_residual_pace_s` | | Yes | [`not_null`](/transform/ci/structural) | actual\_lap\_time\_s minus fuel\_component\_s. Fuel-adjusted counterpart to actual\_lap\_time\_s. | | `delta_vs_actual_lap_s` | | Yes | [`not_null`](/transform/ci/structural) | predicted\_lap\_time\_s minus actual\_lap\_time\_s. 0 when ego == host. | | `deg_interaction_s` | | Yes | [`not_null`](/transform/ci/structural) | (host deg slope - ego deg slope) x age\_in\_stint, slopes from int\_constructor\_deg\_sensitivity at the ego lap's (compound, season). The only host-dependent term that varies within a race, so it is what lets different hosts produce different driver orders. Exactly 0 when ego == host; 0 when no cell exists (wet compounds / low-sample = field-average degradation). | | `host_deg_slope_s_per_lap` | | Yes | [`not_null`](/transform/ci/structural) | Host constructor's deg slope for the ego lap's compound; 0 when no cell. | | `ego_deg_slope_s_per_lap` | | Yes | [`not_null`](/transform/ci/structural) | Ego constructor's deg slope for the ego lap's compound; 0 when no cell. | | `cliff_interaction_s` | | Yes | [`not_null`](/transform/ci/structural), [`expect_column_values_to_be_between`](/transform/ci/range-and-domain) | severity x \[hinge(host) - hinge(ego)] where hinge(c) = GREATEST(0, age - field\_onset - cliff\_onset\_shift(c)). The nonlinear host-dependent term: it only fires once tyres approach/pass the cliff, reordering drivers on long stints. Exactly 0 when ego == host. Guardrail-clipped to +/-2 s. | | `host_cliff_shift_laps` | | Yes | [`not_null`](/transform/ci/structural) | Host constructor's cliff-onset shift (laps) for the ego lap's compound; 0 when no cell. | | `ego_cliff_shift_laps` | | Yes | [`not_null`](/transform/ci/structural) | Ego constructor's cliff-onset shift (laps) for the ego lap's compound; 0 when no cell. | | `recombination_confidence` | | Yes | [`not_null`](/transform/ci/structural), [`expect_column_values_to_be_between`](/transform/ci/range-and-domain) | Continuous confidence in recombination \[0, 1] = host\_obs\_factor (panel\_obs / (panel\_obs + 50)) × the lap's correction\_weight. Degrades smoothly when the host has sparse panel data or the lap was soft-down-weighted. | | `host_constructor_pace_se_s` | | Yes | [`not_null`](/transform/ci/structural) | SE-propagation ingredient: SE of the host constructor's structural pace (0 when no panel cell). Aggregated into predicted\_mean\_lap\_se\_s downstream; cancels in within-scenario ordering since every driver shares the host car. | | `host_deg_slope_sd_s_per_lap` | | Yes | [`not_null`](/transform/ci/structural) | Posterior sd of the host deg slope for the ego lap's compound; 0 when no cell. | | `ego_deg_slope_sd_s_per_lap` | | Yes | [`not_null`](/transform/ci/structural) | Posterior sd of the ego deg slope for the ego lap's compound; 0 when no cell. | | `host_cliff_shift_se_laps` | | Yes | [`not_null`](/transform/ci/structural) | SE (laps) of the host cliff-onset shift; 0 when no cell. | | `ego_cliff_shift_se_laps` | | Yes | [`not_null`](/transform/ci/structural) | SE (laps) of the ego cliff-onset shift; 0 when no cell. | | `host_cliff_active` | | Yes | [`not_null`](/transform/ci/structural) | 1.0 when the host car is past its shifted cliff onset on this lap, else 0.0. | | `ego_cliff_active` | | Yes | [`not_null`](/transform/ci/structural) | 1.0 when the ego car is past its shifted cliff onset on this lap, else 0.0. |