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An emergency crew investigates the scene where a bus caught fire and exploded on northbound Interstate 45 in Wilmer, Texas. The bus carrying elderly evacuees from Hurricane Rita caught fire.

Vehicle Fires Involving Buses

NFPA Journal ®, September/October 2006

By Marty Ahrens, NFPA Fire Analysis and Research Division

This analysis was prepared for the National Transportation Safety Board’s (NTSB’s) Public Hearing on Motorcoach Fires on August 8 and 9, 2006 that was called in response to the September 2005 Texas motorcoach fire that claimed 23 lives. The analysis is based on data collected by the U.S. Fire Administration’s (USFA’s) National Fire Incident Reporting System (NFIRS) and NFPA’s annual fire department experience survey. Vehicle fires were identified by NFIRS incident types 130-139 and buses or school buses were identified by mobile property type code 12. This code also includes trackless trolley buses; statistics for this code cannot be broken down further to separate trackless trolleys or school buses from other buses. A proportional share of vehicle fires in which the mobile property type was unknown or not reported are also included in this analysis. For most causal factors, unknown data is allocated proportionally across the known.

NFPA's Fire Analysis Services Manager Marty Ahrens talks about the bus fire report: Audio clips  An overview of the bus fire report  A breakdown of the data on bus fires between 1999 and 2003  The difference between the data analysis provided by the NFPA versus the National Highway Traffic Safety Administration  More audio clips Related information/reports Catastrophic fire - Tables 1 - 3 The details surrounding the deadliest fires of 2005. (PDF 2.5 MB) U.S. Multiple-Death Fires for 2005 On September 21, storm clouds formed along the Texas and Louisiana coast, setting the stage for the largest multiple-death fire in 2005. Highway accident and selected federal motor carrier safety administration public hearing The agenda of the NTSB's Public Hearing on Motorcoach Fires. (PDF, 26 KB) Vehicle fires involving buses and school buses The report presented by NFPA Fire Analysis Services Manager Marty Ahrens. (PDF, 157 KB) Opening statement The opening statement at the public hearing by honorable Kathryn O'Leary Higgins the Board of Inquiry chairman.

Some 2,210 bus or school bus fires, on average, were reported annually from 1999 to 2003. During this five-year period, U.S. fire departments responded to an estimated average of 2,210 bus or school bus fires per year. These fires caused an estimated annual average of 3 civilian deaths, 30 civilian injuries, and $24.2 million in direct property damage per year. From 1999 to 2003, bus or school bus fires accounted for 1 percent of the total reported vehicle fires, 1 percent of the vehicle fire deaths, 2 percent of the vehicle fire injuries, and 2 percent of the vehicle fire property damage. On average, six bus or school bus fires were reported every day.

Reported bus fires rose 4 percent from 2002 to 2003 but the overall trend in recent years has been flat.

Bus and school bus fires are less common on weekends
The peak month for these fires was May; August and September tied for second highest.

December had the smallest number of these fires. Overall, the difference between months was small. Bus and school bus fires were much less frequent on the weekend than the rest of the week, with just 8 percent on Sunday and 11 percent on Saturday.

73 percent of these fires are reported between 6 a.m. and 6 p.m.
Roughly, one-quarter of all bus and school bus fires are reported between 3 and 6 p.m. The period between 6 and 9 a.m. ranked second highest among the three-hour segments.

Many bus and school bus fires occur on non-road properties.

This is important because such properties generally do not fall under the jurisdiction of the National Highway Traffic Safety Administration (NHTSA), the body that regulates highway vehicles. Forty-five  percent of these incidents occurred on streets, roads or driveways; 15 percent were on highways or divided highways. Although driveways are grouped with residential streets and roads in the NFIRS codes, they are generally not considered part of the public road system. Twelve percent occurred in vehicle parking areas, another property outside of NHTSA’s domain.

Equipment or other heat source failures caused three-fifths of the bus and school bus fires.
Some 60 percent of the bus and school bus fires reported originally in Version 5.0 of NFIRS during 1999-2003 resulted from an equipment failure or failure of heat source. Thirty percent were unintentional. There may be some overlap between unintentional and equipment failure. Only 4 percent of bus and school bus fires were intentional.

Mechanical failures and malfunctions were leading contributing factors.
Overall, some type of mechanical failure or malfunction contributed to 59 percent of these fires; some type of electrical failure or malfunction contributed to 25 percent. Collisions or overturns are considered operational deficiencies. Factors in only 10 bus or school bus fires per year (less than 1 percent), these are only included because they are of special interest and the only fires likely to be captured by NHTSA’s incident databases.

NHTSA estimates that in 2004, only one of 275 fatal bus crashes resulted in a fire, and that less than .05 percent of all reported bus crashes resulted in fire.

Design, manufacturing, or installation deficiencies were factors in only 1 percent of the reported bus or school bus fires. The heat source in one-fifth of the bus and school bus fires was radiated or conducted heat from operating equipment; arcing was the heat source in another 20 percent.

The 1999 model year was the most common in bus and school bus fires in 2003.
In 92 percent of the bus and school bus fires reported during 2003 for which the model year was known, the model year was 2000 or earlier. Three percent of these fires involved vehicles made before the 1975 model year.

Electrical wire or cable insulation was the item first ignited in 29 percent of the bus and bus fires. Twenty-seven percent of the bus and school bus fires began with the flammable or combustible liquids or gases, piping, or filters.

Marty Ahrens is the manager of NFPA’s Fire Analysis Services.