Three Studies Provide Insights on Fires in Vehicles
October 22, 2012
Fires in vehicles can pose a significant threat to life and property. Fires may result from vehicle crashes or may ignite within engine compartments or wheel wells when mechanical systems fail. With its focus on safety, the U.S. Department of Transportation is interested in mitigating the risk to life and property from vehicle fires.
In technical presentations at the Fires in Vehicles (FIVE) International Conference, Volpe staff presented three papers related to vehicle fire safety that examined (1) fires on motorcoaches, (2) fires on commercial trucks, and (3) passenger rail fire standards.
These papers, presented on behalf of the Federal Motor Carrier Safety Administration (FMCSA) and Federal Railroad Administration (FRA), provide insights into ways to prevent and mitigate the consequences of vehicle fires. Volpe staff in the Center for Safety Management Systems and Center for Infrastructure Systems and Engineering authored these papers and presented them at the Chicago, IL, conference in September 2012.
Neil R. Meltzer, Gregory Ayres, and Minh Truong
This paper is a summary of a project report of the same title prepared for FMCSA. The project was initiated in response to the 2005 tragic fire in Texas that resulted in the deaths of 23 nursing home residents during evacuation prior to Hurricane Rita. The subsequent National Transportation Safety Board (NTSB) accident investigation used preliminary study findings and called for continuation of data compilation and analysis to understand the scope and causes of the motorcoach fire problem and, in particular, how the responsible oversight agencies might help prevent such events. The final report was also incorporated into the DOT Motorcoach Safety Action Plan.
Motorcoaches are defined as buses that are designed for the long-distance transport of more than 30 passengers, that have integral construction with an elevated passenger deck located above a baggage compartment, and that are at least 35 feet long. Motorcoach fire data to support the study were pulled from a number of data sources including the National Fire Incident Reporting System, Motor Carrier Management Information System (MCMIS), State Data System (SDS), Fatality Analysis and Reporting System (FARS), and R. L. Polk and Co.
The report identifies that, on average, there are 160 motorcoach fires reported per year, with 95 percent resulting in no direct injuries and fatalities. However, some motorcoach fires may not be captured in these data sources if, for example, they occur on private property or do not result in significant injuries or monetary damages. Motorcoaches of model years 1998-2002 had a disproportionate number of fires compared to older models. The most frequently identified fire origin is the engine compartment, followed closely by wheel wells, together comprising 70 percent of reported fires. Moreover, there is clear evidence from motorcoach inspections that vehicle maintenance problems are associated with future fire occurrences. The findings will help FMCSA determine appropriate fire risk-reduction measures for motorcoaches, including improved data reporting standards and possible adjustments to the state inspection programs to target specific fire precursors.
Jonathan Pearlman and Neil Meltzer
While perhaps less well-known than motorcoach fires and less prevalent than truck crashes, fires involving commercial trucks are an increasing concern for public safety and motor carrier operations. Recognizing a knowledge deficit that could be alleviated with further research, FMCSA leveraged Volpe expertise in analyzing commercial motor vehicle fires and crashes to investigate the magnitude, trends, and causes of truck fires. This study used data sources similar to the motorcoach study and refined the prior methods for identifying and characterizing vehicle fires of interest.
Fatal fires involving commercial trucks represent 17 percent of all fatal highway fire incidents, though commercial trucks are only 3.5 percent of registered vehicles. The authors report that commercial motor vehicle fires are most common among trucks over 33,000 pounds in weight (GVWR Class 8), with the frequency of truck fire fatalities six times greater than that of other motor vehicles. Interestingly, analysis showed that truck fires occur with greater likelihood in the days following a crash. Also, unlike fatal crashes without a fire, the truck is the striking vehicle in the majority of multi-vehicle fatal fire incidents. The report cites implications from these findings for enhanced policy and industry practices, as well as addressing needed improvements in data available for future research.
Stephanie H. Markos and Melissa Shurland
Although the number of passenger train fires has been historically low, the consequences can be catastrophic when a fire does occur. FRA has long recognized the importance of railroads to ensure a high level of passenger rail equipment fire safety. In 1999, FRA issued regulations for new and existing rail equipment, which were clarified and updated in 2002. The two primary requirements are for passenger railroads to:
- conduct fire hazard analyses to assess and resolve hazards, and
- comply with flammability, smoke emission, and fire endurance criteria for certain interior materials.
In addition, the American Public Transportation Association (APTA) developed a recommended practice to assess the fire risk for existing passenger rail equipment that supplements the FRA regulations. The authors of this study conducted a high-level comparison of the regulations and standards that apply to passenger trains operated in the U.S. and Europe. This analysis is intended to assist FRA in determining how to enhance the fire safety performance of passenger rail cars.