Topical Fire Report Series

U.S. Department of Homeland Security • U.S. Fire Administration

National Fire Data Center • Emmitsburg, Maryland 21727

www.usfa.dhs.gov/statistics/reports/index.shtm

Volume 9, Issue 1 / September 2008

Highway Vehicle Fires

continued on next page

Findings

■ Approximately one in six fires is a highway vehicle fire. This does not include the 

tens of thousands of fire department responses to highway vehicle accident sites. 

■ Unintentionally started fires and the failure of equipment are the leading causes of 

highway vehicle fires. 

■ Eighty-four percent of highway vehicle fires occur in passenger vehicles.

■ Sixty-two percent of highway vehicle fires and 34 percent of fatal highway vehicle 

fires originate in the engine area of the vehicle.

■ Where a contributing factor is noted, the leading factor contributing to the ignition of 

highway vehicle fires is mechanical failures (47 percent).

■ Insulation around electrical wiring (28 percent) and flammable liquids in the engine 

area (21 percent) are the items first ignited in highway vehicle fires. 

■ Fifty-seven percent of fatal vehicle fires are the result of a collision. 

These short topical reports are designed 

to explore facets of the U.S. fire problem 

as depicted through data collected in 

USFA’s National Fire Incident Reporting 

System (NFIRS). Each topical report briefly 

addresses the nature of the specific fire or 

fire-related topic, highlights important findings from the data, and may suggest other 

resources to consider for further information. Also included are recent examples of 

fire incidents that demonstrate some of the 

issues addressed in the report or that put 

the report topic in context.

From 2004 to 2006, an estimated 258,500 highway vehicle (automobiles, vans, trucks) fires occurred each 

year. These highway vehicle fires account for 16 percent of 

fires responded to by fire departments across the Nation. 

This topical report addresses the characteristics of highway vehicle fires reported to the National Fire Incident 

Reporting System (NFIRS) between 2004 and 2006.

Highway vehicle fires represent approximately 90 percent of 

all vehicle fires and resulted in an average of approximately 

490 deaths, 1,275 injuries, and $1 billion in property loss 

each year.1

Table 1 presents losses, averaged over this 3-year period, of 

highway vehicle fires and all reported fires. The first set of 

loss figures are losses averaged over all fires and highway 

vehicle fires. The second set is average losses only when a 

loss occurs.2

Table 1. Loss Measures for All Fires and Highway Vehicle Fires 

(3-year average, 2004–2006)

MEASURE ALL FIRES HIGHWAY VEHICLE FIRES

Average loss:

 Fatalities/1,000 fires 2.0 2.6 

 Injuries/1,000 fires 10.2 4.5 

 Dollar loss/fire $5,918 $3,080

Average per fire loss for fires with loss:

 Fatalities/fire 1.2 1.2 

 Injuries/fire 1.3 1.1

 Dollar loss/fire $24,394 $6,464 

Source: NFIRS 5.0.

Note: Average loss for fatalities and injuries is computed per 1,000 fires; for fires with losses, these statistics are computed per fire.
TFRS Volume 9, Issue 1/ Highway Vehicle Fires Page 2

continued on next page

One of the challenges in the analysis of NFIRS vehicle fire 

data is the large number of unknown, undetermined, or 

unavailable entries reported. For example, in the following 

analysis of the heat source and items first ignited in highway 

vehicle fires, the undetermined entries comprise 50 percent 

and 57 percent of the data respectively, making it difficult to 

establish any concrete conclusions. 

Types of Highway Vehicle Fires

The majority of highway vehicle fires, 84 percent, occur 

in nontransport passenger vehicles; 68 percent of highway 

vehicle fires occur in standard passenger vehicles, another 

16 percent occur in some other type of passenger vehicle, 

and less than 1 percent occur in buses. Only 7 percent of 

highway vehicle fires occur in nonpassenger vehicles: 6 

percent of highway vehicle fires occur in transport vehicles, 

with freight transport vehicles accounting for the majority 

of these fires, and less than 1 percent occur in other types 

of vehicles. In the remaining 9 percent of highway vehicle 

fires, the type of vehicle was not reported (Table 2).

Table 2. Types of Highway Vehicle Fires 

(2004–2006)

TYPE OF VEHICLE PERCENT OF HIGHWAY 

VEHICLE FIRES

Passenger road vehicle 84.3

 Passenger vehicle 68.3

 Passenger or road vehicles, other 15.5

 Buses 0.6

Transport vehicle 6.4

 Freight road transport vehicle 6.3

 Rail transport vehicle 0.1

 Water transport vessel <0.1

 Air transport vehicle <0.1

Other vehicle 0.8

 Mobile property, other 0.5

 Industrial, construction, agricultural vehicles 0.3

 Special purpose vehicle <0.1

No entry/Undetermined 8.5

Total 100.0

Source: NFIRS 5.0.

Notes: Totals may not add due to rounding.

No Entry/Undetermined includes incidents where the mobile property type was designated as “None.”
TFRS Volume 9, Issue 1/ Highway Vehicle Fires Page 3

Causes of Highway Vehicle Fires

As shown in Figure 1, unintentionally caused fires account 

for 29 percent of vehicle fires. These fires may be the 

result of either careless behavior or accidental actions. 

Intentionally set fires constitute only 7 percent of vehicle 

fires. NFIRS no longer collects information on suspicious 

fires that may have been intentionally set.3

 As a result, 

intentional fires may be undercounted. Moreover, due to the 

volume of fires, many automobile fires are not investigated 

for possible arson. 

The failure of equipment or the heat source is the cause 

of 28 percent of vehicular fires. These fires are generally a 

result of mechanical problems, ranging from a faulty design 

in the vehicle to an improperly installed device.

Determining the cause of vehicle fires is often challenging. 

As a result, in 23 percent of the vehicle fires no cause was 

determined after investigation. 

Unintentional

0.0 5.0 10.0 15.0 20.0 25.0 30.0

Failure of equipment 

or heat source

Cause under investigation

Intentional

Exposure

Act of nature

Unknown/Invalid entry

Cause undetermined 

after investigation

Percent of incidents where 

cause of ignition determined

Percent of all reported 

incidents

28.9

27.7

27.7

26.6

22.9

22.0

10.5

10.1

7.1

6.8

2.6

2.5

0.3

0.2

4.0

Percent

Where Highway Vehicle Fires Start 

(Area of Fire Origin)

Not surprisingly, an overwhelming majority (94 percent) 

of highway vehicle fires originate within the vehicle itself 

(Figure 2). In fact, 62 percent of highway vehicle fires 

originate in the engine, running gear4

, or wheel areas of the 

vehicle. The second most common area of origin is in the 

passenger area of the vehicle (16 percent).

Figure 1. Causes of Highway Vehicle Fires 

(2004–2006) 

Source: NFIRS 5.0.

Note: The chart reflects 321,447 total entries, 308,553 valid entries, and 12,894 blank or invalid.

continued on next page
TFRS Volume 9, Issue 1/ Highway Vehicle Fires Page 4

Figure 2. Area of Fire Origin in Highway Vehicles 

(2004–2006)

Source: NFIRS 5.0.

Note: The chart reflects 321,447 total entries, 280,501 valid entries, and 40,946 undetermined entries.

Engine area, running gear, 

wheel area

0.0 70.0

Operator/Passenger area of 

transportation equipment

Cargo/Trunk area—all vehicles

Exterior, exposed surface

Fuel tank, fuel line

Separate operator/control area 

of transportation equipment

Undetermined

Vehicle area, other

1.8

1.5

0.3

0.2

10.0 20.0 30.0 40.0 50.0 60.0

Percent of fires where area 

of fire origin determined

Percent of all reported fires

All other 5.6

4.9

12.7

15.8

7.2

6.3

3.7

3.2

3.2

2.8

62.4

54.5

13.7

Percent

How Highway Vehicle Fires Start (Heat 

Source)

Sixty-two percent of highway vehicle fires derive their heat 

source from powered equipment (Figure 3). Fittingly, the 

subcomponents of this category comprise four of the top 

five leading sources of heat in all highway vehicle fires—heat 

from powered equipment (21 percent); radiated or conducted heat from operating equipment (16 percent); electrical arcing (16 percent); and spark, ember, or flame from 

operating equipment (9 percent). 

The next leading category of heat sources in highway vehicle 

fires is from hot or smoldering objects (12 percent). This 

includes fires igniting from hot embers or ashes, sparks that 

result from friction, and other hot materials.

As shown in Figure 3, an additional 10 percent of highway vehicle fires derive their heat source from other open 

flames or smoldering objects. This includes backfire from 

the engine and heat from cigarettes, cigars, matches, torches, 

and the like. 

continued on next page
TFRS Volume 9, Issue 1/ Highway Vehicle Fires Page 5

Figure 3. Sources of Heat in Highway Vehicle Fires

(2004–2006)

Source: NFIRS 5.0.

Note: The chart reflects 321,447 total entries, 160,176 valid entries, and 161,271 undetermined entries.

Heat from powered equipment

0.0 70.0

Hot or smoldering object

Heat source: other

Heat spread from another fire

Multiple heat sources 

including multiple ignitions

Explosive, fireworks

Undetermined

Heat from other open flame or 

smoldering materials

1.4

0.7

1.3

0.7

10.0 20.0 30.0 40.0 50.0 60.0

Percent of incidents where 

heat source determined

Percent of all reported fires

Chemical, natural heat source 0.7

0.4

50.2

11.8

9.7

4.8

9.3

4.6

3.9

1.9

61.9

30.8

5.9

Percent

What Ignites

Forty-one percent of the items first ignited in highway 

vehicle fires fall under the category of general materials. This 

category includes materials such as tires, insulation around 

electric wire and cables, trash, and fabric. The insulation 

around electrical wiring or other cables is the most common 

item to be ignited initially not only within this category, but 

in all highway vehicle fires (28 percent). Interestingly, while 

it is often assumed that vehicle fires commonly originate 

with the tires of the vehicle, tires are the item first ignited in 

only 3 percent of highway vehicle fires. 

The second leading category of items first ignited is liquids, 

piping, and filters (31 percent). This category primarily 

includes fuel in various locations in the vehicle. Not unexpectedly, fuel from the engine area is the leading item first 

ignited within this category, and is the second most common item first ignited in highway vehicle fires overall (21 

percent) due to its combustibility. Flammable liquids and 

gases in general account for 28 percent of items first ignited 

(Figure 4).

continued on next page
TFRS Volume 9, Issue 1/ Highway Vehicle Fires Page 6

Figure 4. Item First Ignited in Highway Vehicle Fires 

(2004–2006) 

Source: NFIRS 5.0.

Note: The chart reflects 321,447 total entries, 139,298 valid entries, and 182,149 undetermined entries.

General materials

0.0

Liquids, piping, filters

Furniture, utensils

Organic materials

Soft goods, wearing apparel

Storage supplies

Undetermined

Item first ignited, other

1.4

0.6

0.7

0.3

60.0

Adornment, recreational 

materials, signs

0.2

0.1

56.7

31.1

16.0

6.9

7.3

3.2

2.0

0.9

41.2

17.9

13.5

Percent

10.0 20.0 30.0 40.0 50.0

Percent of incidents where 

item first ignited determined

Percent of all reported 

incidents

Factors Contributing to Ignition

By far, the leading factor contributing to the ignition of 

highway vehicle fires is mechanical failures (47 percent). 

These mechanical failures can include a leak or break in 

a component of the vehicle, automatic or manual control 

failures, or the use of an improper type of fuel. Within this 

category, unspecified mechanical failures (29 percent) are 

the leading factors contributing to the ignition of highway 

vehicle fires, followed by a leak or break in a component of 

the vehicle (11 percent). 

Electrical failures such as short circuits are the next leading 

factors at approximately 23 percent. The misuse of a material, such as spilling flammable liquid or gas too close to 

the vehicle, is the next leading factor at approximately 12 

percent (Figure 5).

continued on next page
TFRS Volume 9, Issue 1/ Highway Vehicle Fires Page 7

Figure 5. Factors Contributing to Ignition of Highway Vehicle Fires (Where Specified)

(2004–2006)

Source:NFIRS 5.0.

Notes: 1) Includes incidents where factors that contributed to the ignition of the fire were specified. Multiple factors contributing to fire ignition may be noted for each incident.

2) 129,846 entries where factor contributing to ignition was specified.

Mechanical failure

0.0

Electrical failure

Fire spread or control

Factors contributing to 

ignition, other

Operational deficiency

Design, manufacture, 

installation deficiency

Misuse of material or product

0.8

Natural condition 0.5

7.0

Percent

5.0 10.0 15.0 20.0 25.0 30.0 35.0 40.0 45.0 50.0

47.2

23.2

11.9

7.0

6.8

When They Occur

As shown in Figure 6, highway vehicle fires occur mainly in 

the afternoon and evening, peaking from 3 p.m. to 6 p.m. 

Fires occur the least often in the morning hours from 4 a.m. 

to 7 a.m.

Figure 7 shows that vehicle fires occur nearly uniformly 

throughout the year. Highway vehicle fires peak in midsummer in July (10 percent), possibly due to elevated outdoor 

temperatures or increased vehicle use. 

continued on next page
TFRS Volume 9, Issue 1/ Highway Vehicle Fires Page 8

Figure 6. Time of Alarm for Highway Vehicle Fires

(2004–2006)

Source: NFIRS 5.0.

Note: 321,447 total entries.

Figure 7. Highway Vehicle Fires by Month

(2004–2006)

Source: NFIRS 5.0.

Note: 321,447 total entries.

3.6

0.0

7.0

1.0

2.0

3.0

4.0

5.0

6.0

Mid-1 AM

1 AM-2 AM

2 AM-3 AM

3 AM-4 AM

4 AM-5 AM

5 AM-6 AM

6 AM-7 AM

7 AM-8 AM

8 AM-9 AM

9 AM-10 AM

10 AM-11 AM

11 AM-12 PM

12 PM-1 PM

1 PM-2 PM

2 PM-3 PM

3 PM-4 PM

4 PM-5 PM

5 PM-6 PM

6 PM-7 PM

7 PM-8 PM

8 PM-9 PM

9 PM-10 PM

10 PM-11 PM

11 PM-Mid

3.3 3.2

2.9

2.6 2.4 2.6

3.1

3.3

3.4

3.8

4.3

4.9

5.1

5.6

6.0 6.1 6.2

5.6

5.0

4.6 4.5

4.2

3.9

Percent

8.0

7.3

8.1

8.3

8.6

9.0

9.8

9.1

8.4

8.1

7.6 7.7

0.0

2.0

4.0

6.0

8.0

10.0

12.0

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec

Percent

continued on next page
TFRS Volume 9, Issue 1/ Highway Vehicle Fires Page 9

Fatal Highway Vehicle Fires

Where the information on the area of fire origin is available, 

94 percent of fatal highway fires originate in the vehicle 

area, and result in 94 percent of highway vehicle fire deaths. 

Of these fatal fires, the leading area of origin in both fatal 

highway fires and highway fires in general is the engine area, 

at 34 percent and 62 percent, respectively. Fires that originate here are by far the deadliest, accounting for 34 percent 

of all deaths. Fires that originate in the fuel tank account for 

2 percent of highway vehicle fires, but 16 percent of fatal 

fires and 18 percent of deaths.

The heat source in 53 percent of fatal fires with a known 

origin comes from powered equipment and also accounts 

for 53 percent of highway vehicle fire deaths. Within this 

category, sparks, embers, or flames from operating equipment account for 9 percent of highway vehicle fires, but are 

the leading source of fatal fires at 21 percent.

Where the necessary data are available, liquids (most notably 

gasoline), piping, and filters were the items first ignited in 

68 percent of fatal highway vehicle fires, causing 71 percent 

of deaths. Of these fires, those involving gasoline from the 

engine were by far the most deadly (41 percent of deaths). 

Within the liquids, piping, and filters category, fuel in or 

from the engine area is the second leading item first ignited 

in highway vehicle fires in general (21 percent), but is by far 

the leading item in both fatal fires (39 percent) and deaths 

(41 percent). Additionally, insulation from electrical wiring 

or cable is responsible for 28 percent of all highway vehicle 

fires, but only 1 percent of fatal fires and 1 percent of deaths.

Gasoline alone is the leading type of material first ignited in 

highway vehicle fires in general (23 percent) as well as fatal 

highway vehicle fires (52 percent). Gasoline is responsible 

for 56 percent of deaths in fatal fires. Flammable liquids in 

general account for 33 percent of all highway vehicle fires, 

67 percent of fatal highway vehicle fires, and 70 percent of 

deaths. While plastic is the second leading type of material first ignited, at 21 percent of all highway vehicle fires, 

it accounts for less than 1 percent of the fatal fires, and less 

than 1 percent of deaths.

Collisions, as a factor contributing to ignition, result in 3 

percent of all highway vehicle fires, but are responsible for 

57 percent of fatal fires. Fatal fires resulting from collisions 

also account for 57 percent of highway vehicle fire deaths. 

Determining the cause of death following a collision, 

however, often is difficult. Was the death the direct result 

of the collision or the fire that ensued? A fire fatality should 

be counted only if a person was trapped and killed by the 

fire, rather than killed on impact and subsequently exposed 

to the fire. Unspecified mechanical failures contribute to 

29 percent of all highway vehicle fires, but are rarely fatal, 

accounting for 3 percent of fatal fires.

Forty-four percent of fatal highway fires begin unintentionally. Six percent of fatal highway fires were set intentionally. 

Thirty-nine percent of fatal fires occur between midnight 

and 7 a.m., especially between 2 and 4 a.m. (14 percent). 

The highest percentages of deaths occur between 3 and 4 

p.m. (7 percent), 3 and 4 a.m. (7 percent), and 6 and 7 a.m. 

(6 percent).

Conclusion

Vehicle fires generally are given less attention than structure 

fires, largely because most people do not realize the extent to 

which they contribute to the fire problem. Highway vehicle 

fires account for 90 percent of vehicle fires, and 16 percent 

of all fires—one of every six fires. Highway vehicle fires also 

account for 14 percent of all fire deaths, and 94 percent of 

vehicle fire deaths.

In the case of collisions, it often is difficult to determine 

whether the fire and ensuing losses are the result of the fire 

alone or from the fire following the collision. As mechanical 

and electrical failure play a large role in these fires, testing 

to determine how and why these fires develop would allow 

engineers to improve future vehicle designs. Additionally, 

public safety programs aimed at educating the public on 

fire and vehicle safety, coupled with initiatives to reduce the 

number of vehicle collisions, would further reduce the number of highway fires and deaths.

continued on next page
TFRS Volume 9, Issue 1/ Highway Vehicle Fires Page 10

Examples

•	 October 2004: The engine of a low-mileage, late-model

sport utility vehicle caught fire. The manufacturer claims 

the fire was caused by incompetent mechanics, while 

mechanics contend that the close proximity of the oil filter to the exhaust system was to blame. Similar fires have 

occurred in over 60 other 2003 or 2004 models made 

by the same manufacturer.5

• 	 January 2008: Three teens were arrested for attempted

arson after stuffing combustibles, such as paper, into the 

gasoline tanks of several cars and then igniting them.6

•	 February 2008: While driving on the highway, a driver

noticed a fire had started in his engine compartment. 

He pulled over and the 1991 Chevy van quickly went 

up in flames. The fire spread up the embankment on the 

side of the road and covered about one-half acre.7

•	 May 2008: A mechanical failure in a vehicle caused the

vehicle to catch fire. The body shop where the car was 

being serviced was damaged in the ensuing fire.8

To request additional information or to comment on this report, visit 

http://www.usfa.dhs.gov/applications/feedback/index.jsp

continued on next page

Related Topics:

■ Motor Vehicle Fires: What You Need to Know, 

FA-243/April 2003, http://www.usfa.dhs.gov/

downloads/pdf/publications/fa-243.pdf

■ Roadway Operations Safety, http://www.usfa.

dhs.gov/fireservice/research/safety/roadway.

shtm

National Fire Incident Reporting System 

Data Specifications for Highway Vehicle 

Fires

Data for this report were extracted from the NFIRS annual 

public data release (PDR) for 2004, 2005, and 2006. Only 

version 5.0 data were extracted.

Highway vehicle fires were defined as:

•	 Incident types 131 (passenger vehicle fire) and 132

(road freight or transport vehicle fire).

•	 Mobile property involved 1 (not involved in ignition, but

burned) and 3 (involved in ignition and burned).

•	 Aid types 3 (mutual aid given) and 4 (automatic aid

given) were excluded to avoid double counting of 

incidents.
TFRS Volume 9, Issue 1/ Highway Vehicle Fires Page 11

Notes: 

1

 As highway vehicles are a major property class, the national estimates are based only on the National Fire Protection Association’s 

(NFPA) annual survey, Fire Loss in the United States. Fires are rounded 

to the nearest 500, deaths to the nearest 5, injuries to the nearest 

25, and loss to the nearest $ million.

2

 The average fire death and injury loss rates computed from 

the NFPA estimates will not agree with average fire death and 

injury loss rates computed from NFIRS data alone. The fire 

death rate computed from NFPA estimates would be (1,000 x

(490/258,500)) = 1.9 deaths per 1,000 highway vehicle fires and 

the fire injury rate would be (1,000 x (1,275/258,500)) = 4.9 

injuries per 1,000 highway vehicle fires. Loss rates for fires with 

losses cannot be computed from the NFPA estimates.

3

 While the term “suspicious” is not used currently in NFIRS 5.0, 

information still is collected on fires that may be intentionally set 

and may be suspicious or believed to be arson. These fires can be 

coded as fires “under investigation.” However, not all fires coded 

as “under investigation” are necessarily suspicious or believed to be 

arson.

4

 The running gear of a vehicle generally refers to components that 

transfer power from the engine and deliver it to the wheels, e.g., 

transmission, drive shaft, differential.

5

 Jeremy W. Peters, “Why Are Honda CR-V’s Catching Fire?,” 

NYTimes.com, October 12, 2004, http://www.nytimes.

com/2004/10/12/business/12honda.html?n=Top/Reference/

Times%20Topics/Subjects/C/Consumer%20Product%20Safety&_

r=1&adxnnl=1&oref=slogin&adxnnlx=1214251522-tMnY/

qjLJ8NrJfuFQYw8RQ (accessed May 28, 2008).

6

 Michael P. McConnell, “Teens face arson charges for attempting 

to ignite cars,” DailyTribune.com, January 16, 2008, http://www.

dailytribune.com/stories/011608/loc_n3001.shtml (accessed 

June 2, 2008).

7

 Melanie Davis, “Vehicle fire turns into brush fire Monday morning on U.S. 421,” WataugaDemocrat.com, February 11, 2008, http://

www.wataugademocrat.com/2008/0211/0211carfire.php

(accessed May 28, 2008).

8

 “Car destroyed, building damaged during vehicle fire,” 

HickoryRecord.com, May 26, 2008, http://www.hickoryrecord.com/

servlet/Satellite?pagename=HDR/MGArticle/HDR_BasicArticle

&c=MGArticle&cid=1173355566758&path= (accessed May 28, 

2008).