{
  "sources": {
    "sms_inspection": {
      "dataset_id": "rbkj-cgst",
      "dataset_name": "SMS Input - Inspection",
      "dataset_url": "https://data.transportation.gov/d/rbkj-cgst",
      "rows_updated_at": "2026-10-13T08:22:41+00:00",
      "extract": "sms_inspection",
      "columns": [
        "unique_id",
        "dot_number",
        "insp_date",
        "report_state",
        "insp_level_id",
        "driver_oos_total",
        "vehicle_oos_total",
        "oos_total",
        "unsafe_insp",
        "fatigued_insp",
        "dr_fitness_insp",
        "subt_alcohol_insp",
        "vh_maint_insp",
        "hm_insp",
        "basic_viol",
        "unsafe_viol",
        "fatigued_viol",
        "dr_fitness_viol",
        "subt_alcohol_viol",
        "vh_maint_viol",
        "hm_viol"
      ],
      "where": null,
      "row_count": 5853762,
      "content_sha256": "39ae1dffcd0b5852cc6dc403dc5d217fb555e181b829671c48667191033a6c3b",
      "downloaded_at": "2026-11-07T02:12:47+00:00",
      "file": ".research-cache/fmcsa/sms_inspection.csv"
    },
    "sms_violation": {
      "dataset_id": "8mt8-2mdr",
      "dataset_name": "SMS Input - Violation",
      "dataset_url": "https://data.transportation.gov/d/8mt8-2mdr",
      "rows_updated_at": "2026-10-13T07:31:00+00:00",
      "extract": "sms_violation",
      "columns": [
        "unique_id",
        "dot_number",
        "insp_date",
        "viol_code",
        "basic_desc",
        "oos_indicator",
        "severity_weight",
        "section_desc",
        "group_desc",
        "viol_unit"
      ],
      "where": null,
      "row_count": 6784490,
      "content_sha256": "5aba98c8672d10a363378667fe4d25708667dd553aaafe249d05749c80267165",
      "downloaded_at": "2026-11-07T02:21:07+00:00",
      "file": ".research-cache/fmcsa/sms_violation.csv"
    },
    "sms_census": {
      "dataset_id": "kjg3-diqy",
      "dataset_name": "SMS Input - Motor Carrier Census Information",
      "dataset_url": "https://data.transportation.gov/d/kjg3-diqy",
      "rows_updated_at": "2026-10-13T08:31:57+00:00",
      "extract": "sms_census",
      "columns": [
        "dot_number",
        "carrier_operation",
        "phy_state",
        "phy_zip",
        "nbr_power_unit",
        "driver_total",
        "authorized_for_hire",
        "exempt_for_hire",
        "private_property",
        "hm_flag",
        "pc_flag",
        "add_date"
      ],
      "where": null,
      "row_count": 2132868,
      "content_sha256": "c6a5c682232caf474f22a1242aaba189692fac26ac9af47943cf14273eb14000",
      "downloaded_at": "2026-11-07T02:22:55+00:00",
      "file": ".research-cache/fmcsa/sms_census.csv"
    },
    "company_census_tx": {
      "dataset_id": "az4n-8mr2",
      "dataset_name": "Company Census File",
      "dataset_url": "https://data.transportation.gov/d/az4n-8mr2",
      "rows_updated_at": "2026-11-06T19:23:25+00:00",
      "extract": "company_census_tx",
      "columns": [
        "dot_number",
        "status_code",
        "carrier_operation",
        "phy_state",
        "phy_cnty",
        "phy_city",
        "phy_zip",
        "power_units",
        "carship",
        "classdef"
      ],
      "where": "phy_state = 'TX'",
      "row_count": 379302,
      "content_sha256": "a92e67941901d8418f9d35b08793c56f8461947f302fd7a3c24083fcc84bde5d",
      "downloaded_at": "2026-11-07T02:23:05+00:00",
      "file": ".research-cache/fmcsa/company_census_tx.csv"
    }
  },
  "inspection_window": {
    "first": "2024-09-25",
    "last": "2026-09-24"
  },
  "population": "\"Active interstate carrier\" means a carrier listed in the SMS Input - Motor Carrier Census file for this SMS run (FMCSA describes the file as registration data for active interstate and intrastate hazmat carriers) with carrier_operation 'A' (interstate) and a physical address in one of the 50 states or D.C. Texas means phy_state = 'TX'.",
  "active_definition_note": "The FMCSA Company Census File uses its own status field. By that file's definition (status_code 'A', carrier_operation 'A'), 57,070 Texas interstate carriers were active on 2026-11-06, compared with 53,222 in the SMS census used here. The two files measure different things on different dates; this study uses the SMS census throughout so carriers, inspections, and violations come from the same run.",
  "geography": "Physical (registered) address on the carrier's FMCSA registration. It is not where the carrier operates or where inspections happened. Regions use the county code in the Company Census File; county groups are study-defined core counties, listed in texas_regions.csv.",
  "county_enrichment": "County codes come from the Company Census File retrieved 2026-11-07 (portal data updated 2026-11-06), a later snapshot than the SMS run of 2026-10-13. 136 Texas interstate carriers in the SMS census had no Company Census record in that snapshot and are not assigned to any county group.",
  "fleet_size": "nbr_power_unit as self-reported on the carrier's MCS-150. Bands: 1 power unit, 2-10 power units, 11-50 power units, 51-150 power units, 151+ power units; zero or missing is reported separately.",
  "inspections": "Rows of the SMS Input - Inspection file (inspections used in the SMS run, 24-month window). Attributed to the inspected carrier's USDOT number.",
  "driver_oos_rate": "Inspections at levels 1, 2, 3, 6 with at least one driver out-of-service violation, divided by all inspections at those levels.",
  "vehicle_oos_rate": "Inspections at levels 1, 2, 5, 6 with at least one vehicle out-of-service violation, divided by all inspections at those levels.",
  "violations": "Rows of the SMS Input - Violation file (violations used in SMS calculations), attributed by USDOT number.",
  "suppression": "Rates require at least 1,000 inspections in the denominator; smaller cells are shown as suppressed. Carrier counts and carrier shares are exact and are not suppressed.",
  "comparisons": "Differences under 1.0 percentage point are described as about the same.",
  "rounding": "Percentages rounded to one decimal place. Counts are exact.",
  "quality_checks": {
    "inspection_rows": 5853762,
    "duplicate_inspection_ids": 0,
    "violation_rows": 6784490,
    "violations_linked_to_an_inspection_row": 6784490,
    "violations_linked_share_pct": 100.0,
    "duplicate_carrier_dot_numbers": 0,
    "inspections_matched_to_census_carrier": 5853762,
    "inspections_matched_share_pct": 100.0,
    "hos_violation_rows": 612853,
    "hos_violation_count_from_inspection_file": 612853
  },
  "limitations": [
    "Registered address is not operating territory; many Texas-based carriers run interstate lanes and many inspections of them occur outside Texas.",
    "Power units and drivers are self-reported on the MCS-150 and can be out of date.",
    "Inspection exposure is not random: enforcement focus, routes, and facility locations affect who is inspected.",
    "Out-of-service rates describe inspections, not carriers, and are not crash-risk measures.",
    "The SMS files contain only inspections and violations used in SMS calculations for the month's run.",
    "Region results reflect study-defined county groups, not official metropolitan statistical areas.",
    "Texas-versus-national differences in out-of-service rates are descriptive. They can reflect where and how carriers are inspected (inspection level, enforcement practice, routes), not only carrier behavior."
  ]
}