Sources and methodology

Every table on Texas Mobility Outlook is compiled from a published public record. This page lists the main sources, the definitions that change what a number means, and the checks applied before a figure is published. The full directory of downloadable datasets is at the foot of the page.

Main sources

The TxDOT crash reports are the base for most crash tables.¹ Federal figures come from FARS and FMCSA’s analysis tools.^2,3 Congestion ranks come from TTI’s 2025 edition.⁴ Each page cites the exact table, year and edition it uses.

Definitions that change the count

Reportable crash. TxDOT counts a crash when a motor vehicle in transport on a trafficway causes injury, death or apparent property damage of at least $1,000.⁵ Crashes below that line, and crashes no officer reported, are not in the tables.

Serious injury. TxDOT’s “suspected serious injury,” formerly “incapacitating injury.” Pages abbreviate fatal plus serious-injury crashes as KA, the term used in local safety plans.

Commercial motor vehicle crash (TxDOT). A crash where the officer marked a vehicle as a commercial motor vehicle on the crash report. Counts include everyone killed or injured in the crash, not only truck occupants.⁵

Large truck (NHTSA). A truck with a gross vehicle weight rating over 10,000 pounds, commercial or not. Buses are excluded.⁶

Truck and bus (FMCSA). FMCSA starts from FARS and adds buses. These three counts measure different things, and the comparison in research note 3 shows how far apart they run.

Annual average daily traffic (AADT). TxDOT’s estimate of the vehicles passing a count station on an average day of the year.

Geography. City of Houston figures cover crashes inside city limits on every road, freeways included. Harris County figures cover the whole county. The H-GAC region covers eight counties: Harris, Fort Bend, Montgomery, Galveston, Brazoria, Waller, Chambers and Liberty.

Data dates and revisions

Agencies revise. TxDOT’s 2025 crash reports reflect crash reports processed as of April 7, 2026, and its 2015-2024 tables were reissued with data as of April 9, 2025.⁷ NHTSA’s yearly fact sheets use a preliminary FARS file that is later finalized.⁶ Each data page states the data date it uses in its data record, and tables are updated when a new edition appears.

How tables are checked

• Rows are checked against totals. TxDOT’s county and city rows were checked so the severity columns add up to the printed crash total.
• Figures are read from the source document, not from news summaries of it, wherever the document is public.
• Calculations are labeled. Shares, sums, percent changes and indexes that Texas Mobility Outlook computes are labeled on the page and in the dataset notes. Agency figures keep the precision the agency published.
• Gaps stay gaps. A missing year shows as “n/a.” A figure Texas Mobility Outlook could not verify appears in a box marked “Verified data required.”

Reusing the data

Every dataset below downloads as a CSV file. Compiled tables are available under the Creative Commons Attribution 4.0 license. Credit “Texas Mobility Outlook (tmohouston.net)” and name the original agency, as in: “Source: TxDOT crash data, compiled by Texas Mobility Outlook.”

Photographs are not covered by that license. Each carries its own credit and license.

Questions about a dataset go through the contact page. Errors are handled under the corrections policy.