This report provides one-way frequencies for all the vehicles in the University of Michigan Transportation Research Institute's file of Trucks Involved in Fatal Accidents (TIFA), 2001. The 2001 TIFA file is a census of all medium and heavy trucks involved in a fatal accident in the United States. The TIFA database provides coverage of all medium and heavy trucks recorded in the Fatality Analysis Reporting System (FARS) file. TIFA combines vehicle, accident, and occupant records from FARS with information about the physical configuration and operating authority of the truck from the TIFA survey.

To determine the major event pathways that result in sport utility vehicle (SUV) rollover, researchers at the University of Michigan Transportation Research Institute examined SUV rollover cases selected from the National Automotive Sampling System crashworthiness data system files for 1999 to 2001. Selected SUVs included the Ford Explorer, Jeep Cherokee, Chevrolet Blazer, Toyota 4-Runner, and GMC Jimmy for model years 1989 to 2001. Researchers coded up to six pre-rollover events, along with the stability of the vehicle (tracking or skidding) after each event. In addition, crash avoidance and recovery maneuvers were recorded, along with the rollover initiation type, location of rollover initiation, direction of roll, number of quarter turns of roll, location of roll, and surface condition at rollover initiation. Approximately 34% of SUV rollovers began with a loss of control caused by tire saturation, and about 75% of the loss-of-control cases were on icy, wet, or snowy roads. Of the SUVs that ran off the road as the first event, 47% returned to the road before rolling over, and of these, 76% were tracking (presumed under control) before initial road departure. Between 40% and 49% of SUV rollover crashes experienced yaw instability while still on the roadway before roll. These rollovers may be addressed by electronic stability control devices if such devices can increase the control limits of the vehicle.

This report provides one-way frequencies for all the vehicles in the University of Michigan Transportation Research Institute's file of Trucks Involved in Fatal Accidents (TIFA), 2002. The 2002 TIFA file is a census of all medium and heavy trucks involved in a fatal accident in the United States. The TIFA database provides coverage of all medium and heavy trucks recorded in the Fatality Analysis Reporting System (FARS) file. TIFA combines vehicle, accident, and occupant records from FARS with information about the physical configuration and operating authority of the truck from the TIFA survey.

In 2000, the Federal Motor Carrier Safety Administration's (FMCSA's) regulatory responsibilities were extended to buses with seating for nine or more occupants, including the driver, transported for compensation. FMCSA has also begun supporting data collection on buses involved in fatal crashes, to enhance information on the buses involved and the motor carriers that operate them. In response, the Transportation Safety Analysis Division at the University of Michigan Transportation Research Institute (UMTRI) initiated the Buses Involved in Fatal Accidents (BIFA) project to collect much more detailed information about buses involved in fatal crashes. The present study focuses on factors associated with fatal bus crashes involving different bus operator types. Five different carrier types are identified: school, transit, intercity, charter/tour, and "other" bus operators. There are substantial differences between these carrier types that are reflected in many aspects of the crashes they are involved in, including when and where the crashes occur, who is injured in them, the configuration of the crash, the previous driving record of the bus drivers, and the frequency of driving errors related to the crash.