Researcher

This study was performed 

jointly by the Center for

National Truck Statistics,

University of Michigan

Transportation Research

Institute, and the Office of

Data Analysis and Information

Systems, OMCHS, Federal

Highway Administration.

Contract No: DTFH61-96-C0038.

Distribution

This Analysis Brief is being 

distributed according to a 

standard distribution. Direct

distribution is being made to

the Resource Centers and

Divisions.

Availability

This Analysis Brief is available

through the OMCHS Office of

Data Analysis and Information

Systems, Telephone: (202) 

366-1861.

Key Words

large trucks, passenger 

vehicles, driver-related crash

factors, head-on crashes, 

rear- end crashes, sideswipes.

Notice

This Analysis Brief is disseminated under the sponsorship 

of the Department of

Transportation in the interest

of information exchange. 

The Analysis Brief does not

establish policies or regulations, nor does it imply 

FHWA endorsement of the 

conclusions or recommendations. The U.S. Government

assumes no liability for its 

contents or their use.

opposite direction sideswipes, which have a similar crash configuration to head-on crashes,

the passenger vehicle encroached into the truck’s lane over seven times as often as the truck

encroached into the passenger vehicle’s lane (Table 5). In same direction sideswipes, the passenger vehicle encroached into the truck’s lane about two and one half times as often as the

truck encroached into the passenger vehicle’s lane. 

The driver-related factors coding was consistent with this physical evidence. When the 

passenger vehicle encroached into the lane in which the truck was traveling, the encroaching passenger vehicle driver was assigned driver factors in 98 percent of the opposite 

direction sideswipe crashes and 97 percent of the same direction sideswipe crashes. When

the large truck was the encroaching vehicle, the truck driver was coded with driver-related

factors in 79 percent of the opposite direction sideswipe crashes and 83 percent of the same

direction sideswipe crashes. The most common driver-related factor coded for the encroaching vehicles, whether they were a passenger vehicle or a large truck, was running off the

road or out of the traffic lane, both for opposite and same direction sideswipe crashes.

Other Crash Configurations: In all other crash configurations not discussed above, the 

physical evidence does not provide conclusive clues on driver contribution to fatal crashes. 

In the remaining 4,047 fatal crashes in this study, twice as many passenger vehicle drivers as

truck drivers (77 percent versus 33 percent) are coded with driver-related factors (Table 6).

The major factors cited for the drivers are similar to those recorded for the crash configurations already discussed above.

Conclusion

In about one-half of the fatal crashes between one large truck and one passenger vehicle,

physical evidence about each vehicle’s maneuver and position prior to the crash was 

available to help verify the coding of the driver-related factors. In these cases, the 

driver-related factors coding appeared to be consistent with the physical evidence. The 

drivers of vehicles that encroached into the other vehicle’s lane in head-on and sideswipe

crashes and drivers of vehicles that struck the other vehicle in rear-end crashes were assessed

driver-related factors or errors more often than the other driver. In the majority of these

cases, the passenger vehicle driver was attributed with driver-related factors or errors more

often than the driver of the large truck. 

While many of the OMCHS programs focus on motor carrier and truck driver safety, this

analysis supports the importance of focusing on behavior of the drivers of the other 

vehicles. OMCHS already has programs in place, such as No Zone and car-truck proximity

research, that are addressing these issues. However, more comprehensive data on the causes

of large truck/passenger vehicle crashes of all severities would enhance OMCHS’s ability to

develop effective countermeasures and prevent future crashes.

April 1999

Publication No. FHWA-MCRT-99-011

Table 6. 

All Other Fatal Crash* Configurations by Driver-Related Factors.

Number of Times Cited for Drivers

Driver Related Factor Truck Passenger Vehicle

Failure to Yield Right of Way 417 1,622

Failure to Obey Traffic Devices 274 950

Inattentive 92 387

Driving Too Fast 160 358

Ran Off Road/Lane 108 246

Erratic/Reckless Driving 80 150

*Involving one large truck and one passenger vehicle

Source: TIFA 1994–1996
vehicle. In the 8,309 fatal crashes, truck drivers were not

coded with any driver-related crash factors in 73 percent

of the crashes (Table 1). In contrast, only 18 percent of

the passenger vehicle drivers were not coded with a 

driver-related factor (Table 2). In 16 percent of the 

crashes, the large truck was assigned crash factors, while

in 71 percent of the crashes, the passenger vehicle was

assigned crash factors. In 10 percent of the crashes both

drivers were assigned crash factors.

One explanation offered for the disproportionate number of factors attributed to the passenger vehicle driver

is that typically the passenger vehicle driver is killed in

these crashes while the truck driver survives. The hypothesis is that the truck driver is available to give “his side”

of the crash scenario and persuade the reporting police

officer that the other driver was primarily at fault. In 

83 percent of the crashes in the study, the truck driver

survived and the passenger vehicle driver was killed,

while in only 2 percent of the crashes the passenger 

vehicle driver survived and the truck driver was killed.

In 15 percent of the crashes in the study, both drivers

survived and may have been able to describe the crash to

the investigating officer. In 73 percent of these cases, the

passenger vehicle driver was coded with a factor, while

the truck driver was coded with a factor only 34 percent

of the time. The distribution of driver-related factors for

these cases remained close to the overall distribution for

all fatal crashes.

Next, the driver-related factors were examined in light of

the crash configuration to gain further insight in the

validity of the coding of driver-related factors. The TIFA

variable accident type captures the relative movement

and position of the two vehicles prior to impact. Both

the location of the vehicle in regard to its travel lane

prior to impact and which was the striking vehicle can be

determined from this variable. In some types of fatal

crashes, this physical evidence of the crash configuration

strongly suggests that one driver may have contributed

more heavily than the other. 

Four types of crash configurations were examined: 

head-on, rear-end, sideswipe (opposite and same 

direction), and all other configurations. Physical evidence

for head-on and rear-end collisions probably indicates

driver error. In a head-on crash where one vehicle

crossed into the oncoming traffic lane, the evidence may

indicate a greater contribution to the crash on the part

of the driver that left his lane. In a rear-end collision, the 

striking vehicle may have contributed more heavily than

the struck vehicle. The same is often true for sideswipes,

whether the vehicles were going in the same or opposite

directions. The driver that crosses into the other vehicle’s

lane probably contributed more heavily to the crash.

However, in some sideswipes the physical evidence of

where the collision took place is not as clear as for headons and rear-ends. For those cases, coding which vehicle

encroached into the other vehicle’s lane may depend on

witness statements. 

In other types of crashes — mostly angle collisions — the

physical evidence does not give strong clues to implicate

one vehicle or the other in the fatal crash. In one such

Table 1. 

Large Truck Driver-Related Factors in Fatal

Crashes* with a Single Passenger Vehicle

Large Truck Driver Factor Number Percent

Coding

No Truck Driver Factor Coded 6,051 73%

Factor(s) Coded for Truck Driver 1,325 16%

Only

Factor(s) Coded for Truck Driver 830 10%

and Passenger Vehicle

Unknown 103 1%

Totals 8,309 100%

*Involving one large truck and one passenger vehicle

Source: TIFA 1994–1996

Table 2. 

Passenger Vehicle Driver-Related Factors in

Fatal Crashes* with a Single Large Truck

No Passenger Vehicle Driver Number Percent

Factor Coding

No Passenger Vehicle Driver 1,477 18%

Factor Coded

Factor(s) Coded for Passenger 5,875 71%

Vehicle Driver Only

Factor(s) Coded for Passenger 830 10%

Vehicle Driver and Truck Driver

Unknown 127 1%

Totals 8,309 100%

*Involving one large truck and one passenger vehicle

Source: TIFA 1994–1996

All Other

49.0%

Head-On

23.0%

Rear-End

15.0%

Sidewipe 

Opposite

10.0%

Sidewipe 

Same

3.0%

Figure 1. 

Fatal Crashes* by Collision Type

*Involving one large truck and one passenger vehicle

Source: TIFA 1994–1996
vehicle. In the 8,309 fatal crashes, truck drivers were not

coded with any driver-related crash factors in 73 percent

of the crashes (Table 1). In contrast, only 18 percent of

the passenger vehicle drivers were not coded with a 

driver-related factor (Table 2). In 16 percent of the 

crashes, the large truck was assigned crash factors, while

in 71 percent of the crashes, the passenger vehicle was

assigned crash factors. In 10 percent of the crashes both

drivers were assigned crash factors.

One explanation offered for the disproportionate number of factors attributed to the passenger vehicle driver

is that typically the passenger vehicle driver is killed in

these crashes while the truck driver survives. The hypothesis is that the truck driver is available to give “his side”

of the crash scenario and persuade the reporting police

officer that the other driver was primarily at fault. In 

83 percent of the crashes in the study, the truck driver

survived and the passenger vehicle driver was killed,

while in only 2 percent of the crashes the passenger 

vehicle driver survived and the truck driver was killed.

In 15 percent of the crashes in the study, both drivers

survived and may have been able to describe the crash to

the investigating officer. In 73 percent of these cases, the

passenger vehicle driver was coded with a factor, while

the truck driver was coded with a factor only 34 percent

of the time. The distribution of driver-related factors for

these cases remained close to the overall distribution for

all fatal crashes.

Next, the driver-related factors were examined in light of

the crash configuration to gain further insight in the

validity of the coding of driver-related factors. The TIFA

variable accident type captures the relative movement

and position of the two vehicles prior to impact. Both

the location of the vehicle in regard to its travel lane

prior to impact and which was the striking vehicle can be

determined from this variable. In some types of fatal

crashes, this physical evidence of the crash configuration

strongly suggests that one driver may have contributed

more heavily than the other. 

Four types of crash configurations were examined: 

head-on, rear-end, sideswipe (opposite and same 

direction), and all other configurations. Physical evidence

for head-on and rear-end collisions probably indicates

driver error. In a head-on crash where one vehicle

crossed into the oncoming traffic lane, the evidence may

indicate a greater contribution to the crash on the part

of the driver that left his lane. In a rear-end collision, the 

striking vehicle may have contributed more heavily than

the struck vehicle. The same is often true for sideswipes,

whether the vehicles were going in the same or opposite

directions. The driver that crosses into the other vehicle’s

lane probably contributed more heavily to the crash.

However, in some sideswipes the physical evidence of

where the collision took place is not as clear as for headons and rear-ends. For those cases, coding which vehicle

encroached into the other vehicle’s lane may depend on

witness statements. 

In other types of crashes — mostly angle collisions — the

physical evidence does not give strong clues to implicate

one vehicle or the other in the fatal crash. In one such

Table 1. 

Large Truck Driver-Related Factors in Fatal

Crashes* with a Single Passenger Vehicle

Large Truck Driver Factor Number Percent

Coding

No Truck Driver Factor Coded 6,051 73%

Factor(s) Coded for Truck Driver 1,325 16%

Only

Factor(s) Coded for Truck Driver 830 10%

and Passenger Vehicle

Unknown 103 1%

Totals 8,309 100%

*Involving one large truck and one passenger vehicle

Source: TIFA 1994–1996

Table 2. 

Passenger Vehicle Driver-Related Factors in

Fatal Crashes* with a Single Large Truck

No Passenger Vehicle Driver Number Percent

Factor Coding

No Passenger Vehicle Driver 1,477 18%

Factor Coded

Factor(s) Coded for Passenger 5,875 71%

Vehicle Driver Only

Factor(s) Coded for Passenger 830 10%

Vehicle Driver and Truck Driver

Unknown 127 1%

Totals 8,309 100%

*Involving one large truck and one passenger vehicle

Source: TIFA 1994–1996

All Other

49.0%

Head-On

23.0%

Rear-End

15.0%

Sidewipe 

Opposite

10.0%

Sidewipe 

Same

3.0%

Figure 1. 

Fatal Crashes* by Collision Type

*Involving one large truck and one passenger vehicle

Source: TIFA 1994–1996
Researcher

This study was performed 

jointly by the Center for

National Truck Statistics,

University of Michigan

Transportation Research

Institute, and the Office of

Data Analysis and Information

Systems, OMCHS, Federal

Highway Administration.

Contract No: DTFH61-96-C0038.

Distribution

This Analysis Brief is being 

distributed according to a 

standard distribution. Direct

distribution is being made to

the Resource Centers and

Divisions.

Availability

This Analysis Brief is available

through the OMCHS Office of

Data Analysis and Information

Systems, Telephone: (202) 

366-1861.

Key Words

large trucks, passenger 

vehicles, driver-related crash

factors, head-on crashes, 

rear- end crashes, sideswipes.

Notice

This Analysis Brief is disseminated under the sponsorship 

of the Department of

Transportation in the interest

of information exchange. 

The Analysis Brief does not

establish policies or regulations, nor does it imply 

FHWA endorsement of the 

conclusions or recommendations. The U.S. Government

assumes no liability for its 

contents or their use.

opposite direction sideswipes, which have a similar crash configuration to head-on crashes,

the passenger vehicle encroached into the truck’s lane over seven times as often as the truck

encroached into the passenger vehicle’s lane (Table 5). In same direction sideswipes, the passenger vehicle encroached into the truck’s lane about two and one half times as often as the

truck encroached into the passenger vehicle’s lane. 

The driver-related factors coding was consistent with this physical evidence. When the 

passenger vehicle encroached into the lane in which the truck was traveling, the encroaching passenger vehicle driver was assigned driver factors in 98 percent of the opposite 

direction sideswipe crashes and 97 percent of the same direction sideswipe crashes. When

the large truck was the encroaching vehicle, the truck driver was coded with driver-related

factors in 79 percent of the opposite direction sideswipe crashes and 83 percent of the same

direction sideswipe crashes. The most common driver-related factor coded for the encroaching vehicles, whether they were a passenger vehicle or a large truck, was running off the

road or out of the traffic lane, both for opposite and same direction sideswipe crashes.

Other Crash Configurations: In all other crash configurations not discussed above, the 

physical evidence does not provide conclusive clues on driver contribution to fatal crashes. 

In the remaining 4,047 fatal crashes in this study, twice as many passenger vehicle drivers as

truck drivers (77 percent versus 33 percent) are coded with driver-related factors (Table 6).

The major factors cited for the drivers are similar to those recorded for the crash configurations already discussed above.

Conclusion

In about one-half of the fatal crashes between one large truck and one passenger vehicle,

physical evidence about each vehicle’s maneuver and position prior to the crash was 

available to help verify the coding of the driver-related factors. In these cases, the 

driver-related factors coding appeared to be consistent with the physical evidence. The 

drivers of vehicles that encroached into the other vehicle’s lane in head-on and sideswipe

crashes and drivers of vehicles that struck the other vehicle in rear-end crashes were assessed

driver-related factors or errors more often than the other driver. In the majority of these

cases, the passenger vehicle driver was attributed with driver-related factors or errors more

often than the driver of the large truck. 

While many of the OMCHS programs focus on motor carrier and truck driver safety, this

analysis supports the importance of focusing on behavior of the drivers of the other 

vehicles. OMCHS already has programs in place, such as No Zone and car-truck proximity

research, that are addressing these issues. However, more comprehensive data on the causes

of large truck/passenger vehicle crashes of all severities would enhance OMCHS’s ability to

develop effective countermeasures and prevent future crashes.

April 1999

Publication No. FHWA-MCRT-99-011

Table 6. 

All Other Fatal Crash* Configurations by Driver-Related Factors.

Number of Times Cited for Drivers

Driver Related Factor Truck Passenger Vehicle

Failure to Yield Right of Way 417 1,622

Failure to Obey Traffic Devices 274 950

Inattentive 92 387

Driving Too Fast 160 358

Ran Off Road/Lane 108 246

Erratic/Reckless Driving 80 150

*Involving one large truck and one passenger vehicle

Source: TIFA 1994–1996