FMCSA - Large Truck Crash Causation Study

The Large Truck* Crash Causation Study (LTCCS) is based on a three-year data collection project conducted by the Federal Motor Carrier Safety Administration (FMCSA) and the National Highway Traffic Safety Administration (NHTSA) of the U.S. Department of Transportation (DOT). LTCCS is the first-ever national study to attempt to determine the critical events and associated factors that contribute to serious large truck crashes allowing DOT and others to implement effective countermeasures to reduce the occurrence and severity of these crashes.

LTCCS Data
Download the Study Data The study's data are available for download in SAS, Excel and text formats.
LTCCS Case Viewer The LTCCS dataset (above) consists of aggregate data tables. FMCSA has collaborated with the National Highway Transportation Safety Administration to develop a web-based case viewer. The viewer will allow users to filter the study dataset for specific crash types or factors and review the resulting case information. The information available for each case includes a crash summary, photographs, crash scene diagrams, vehicle and driver inspections, and other information for each involved vehicle.
User's Manual (Text-only) The LTCCS Analytical User's Manual provides guidance on the variable definitions and codes for all the data sets included in the study.
Codebook (Text-only) The LTCCS Codebook provides a listing of every variable and code level in each data file, including the distribution of records, code values in the file, labels associated with each code value, data storage type, variable storage length, and format entry, if any. The Codebook also includes an appendix with tables that can be used to estimate standard errors and confidence intervals for estimated totals of variables contained in the data sets.
RESULTS OVERVIEW
Press Release
Report to Congress (Text-only) The Motor Carrier Safety Improvement Act of 1999 (MCSIA), P.L. 106-159, mandated the LTCCS to determine the causes of, and contributing factors to, crashes involving commercial motor vehicles. In March 2006, FMCSA submitted a report to Congress detailing the study's principle findings.
Overview Presentation
Summary Tables An introduction to the study's results are provided in a series of summary tables.
Frequently Asked Questions

ANALYSIS BRIEFS & PRESENTATIONS
LTCCS Summary (2007) This summary presents the results of further analysis of the LTCCS data, including a discussion explaining the difference between a crash's critical event, critical reason and associated factors. The summary also includes a number of analysis tables and a discussion of relative risk.
"Three Stories from the LTCCS: Using the LTCCS for Safety Research" This presentation, by Dan Blower from the University of Michigan Transportation Research Institute, illustrates the strengths and limitations of the LTCCS data using experience from three research projects.
USING THE DATA
Study Methodology Provides the background and methodology of the study, including a discussion about crash causation, critical events and associated factors. It also describes the collaborative effort by FMCSA and NHTSA resulting in a nationally representative sample of 1,000 large truck fatal and serious injury crashes over a three year period.
Using the LTCCS Data (Text-only) This document discusses how statistical analyses of the LTCCS database can be used to investigate crash causes and contributing factors. It defines 10 critical issues for large truck safety, outlines the information needed to address each, assesses how well the LTCCS database fills those needs, and discusses other data that could be used for questions where LTCCS data are not adequate.
Questions, Comments and Requests If you have questions or comments relating to the LTCCS data and its use (such as the weighting of the data), please contact Doug Rickenback, (617) 494-2668, at the US DOT's Volpe National Transportation Systems Center. Inquiries can also be submitted online through our automated feedback feedback system.

*Throughout the study materials and the Website summary tables, "truck" refers to a vehicle designed, used, or maintained primarily for carrying property, with a gross vehicle weight rating or gross combination weight rating of more than 10,000 lbs.