Traffic Safety Facts

Traffic Tech – Technology Transfer Series

Number 349 May 2008

U.S. Department of Transportation 1200 New Jersey Avenue SE., Washington, DC 20590

National Highway Traffic Safety Administration

Occupant Protection Issues Among 

Older Drivers and Passengers

Background

The number of older adults in the United States is expected

to grow dramatically. By the year 2030, adults 65 and older

will make up nearly 20% of the U.S. population. Today, older

people are healthier and living longer. This means that many

older adults will keep their driver licenses longer and will

drive more miles on the roadways than the current generation of older people; hence, they are at increased risk for

involvement in motor vehicle crashes. Unless significant

countermeasures are employed, traffic fatalities for older

adults are projected to double or triple by the year 2030.

Although older adults are reported to use seat belts more

often than any other age group, there is still a significant proportion of older adults who never use seat belts or use them

only part-time. Much of what the National Highway Traffic

Safety Administration knows about the reasons older adults

do not use seat belts is anecdotal, including comfort and convenience issues, the presence of chronic health conditions

such as arthritis, and resistance to seat belt use in general.

The overall purpose of this study was to understand what

factors contribute to seat belt use and nonuse among adults

age 65 and older. In addition, the study was designed to identify what can be done to increase seat belt use among older

adults now and in the future, thereby reducing injuries and

fatalities among the older adult population.

Method

In order to fully comprehend the dynamics behind the decision to use or not use a seat belt and the factors that may

influence seat belt use among seniors, the following activities

were implemented:

A literature review, discussions with experts, and analyses using selected databases;

Fifteen focus groups conducted in four States (Florida,

Iowa, Maryland, and Massachusetts) with older adults

who were part-time users or nonusers of seat belts;

A human factors study in which 54 older adults were

exposed to seat belt systems in three different vehicle

models to measure the likelihood of use and to obtain ratings on comfort and convenience.

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Key Findings

The literature review and data analysis revealed that a variety of factors influence one’s decision to use or not use a

seat belt, including risk perception, road type, trip length,

weather, presence of other vehicle occupants, comfort and

convenience, and physical and health conditions. Major factors contributing to nonuse of seat belts among older adults

are comfort and convenience. Some of the common issues

mentioned by older adults related to comfort and convenience include difficulty reaching for the shoulder belt and

pulling it across the body, the shoulder belt cutting across

the neck, and difficulty inserting the latch plate into the belt

buckle. These problems may be exacerbated by the different

types of physical limitations experienced by older adults due

to aging, such as arthritis, osteoporosis, obesity, and re­cov­ery

from recent chest or abdominal surgery.

During the focus group discussions, several themes emerged

similar to those found in the literature review. Most participants spoke of the discomfort associated with twisting

and turning to reach for and buckle the seat belt. Heavier

participants mentioned the tightness when secured, while

shorter-stature participants complained about the shoulder

belt chafing, choking, or rubbing across the neck. Many participants also mentioned problems with actually inserting

the latch into the buckle portion of the seat belt. Some had

difficulties locating the buckle and re­leasing the latch from

the buckle.

During the focus groups, various aftermarket devices (seat

cushions, pivoting seats, seat belt adjusters, shoulder pads,

belt extenders, and plastic loops) designed to increase comfort and usability of seat belts were presented. The shoulder

pad, belt extender, and plastic loop received extremely positive feedback; thus, these were incorporated into the field

data collection study.

The final stage of the project was a human factors study that

provided detailed observation and measurement of seat belt

use and acceptability. Fifty-four older adults were exposed

to six different safety belt systems and gave ratings regarding comfort, convenience, and likelihood of use. They tested

each of the three test vehicles twice, once with the original

belt system and once with a modified belt that included

one of three aftermarket devices (seat belt extenders, plastic
loops, or shoulder pads). The test vehicles varied in size, belt

configurations, and aftermarket devices:

n	 Compact vehicle: The shoulder belt descends from the

B-pillar with a shoulder belt adjuster on the B-pillar. The

seat belt buckle stalk extends from the seat in proximity

to a relatively small center console. The latch plate was

able to slide along the lap and shoulder belt. The vehicle

had manual seat adjustments and a smaller cabin. A belt

extender aftermarket device was used for this vehicle.

n	 Mid-size vehicle: The shoulder belt descends from the

B-pillar; in this two-door design the B-pillar is substantially further back than in a four-door design. The seat

belt buckle stalk is recessed in the seat alongside a large

console that descends to the floor of the vehicle. The latch

plate was able to slide along the lap and shoulder belt.

The vehicle had both manual and automatic seat adjustments. The plastic loop aftermarket device was used for

this vehicle.

n	 Full-size vehicle: In this design, the shoulder belt originates from the retractors attached to the front passenger

seats. The seat belt buckle stalk protrudes from the seat

in proximity to a medium-sized center console. The latch

plate was sewn directly onto the straps of the lap and

shoulder belt, making it stationary on the belt and requiring a very specific angle in order to be able to insert the

plate into the buckle. A shoulder pad aftermarket device

was used for this vehicle.

A comparison of the three base seat belt systems in the two

front seating positions showed that, overall, the compact

vehicle was rated the most comfortable, easiest to reach

with regard to the shoulder belt, and easiest to buckle by

the older participants. As for the two-door mid-size vehicle, participants cited a number of specific difficulties with

operating the base seat belt system. Most participants had

difficulty locating and reaching for the shoulder belt which

was affixed to the B-pillar, which is further back. Because

the center console in between the two front seats was large

and rigid, most participants had difficulty finding and seeing the buckle that was recessed between the seat back and

seat cushion. The full-size vehicle seat belt is integrated into

the seat back. Many participants had difficulty finding the

shoulder belt and needed to twist around to locate it, and

then twist again to insert the latch into the buckle. As with

the mid-size vehicle, participants had difficulty finding and

seeing the buckle in the full-size vehicle, and felt that the area

around the buckle was too narrow. In addition, the design of

the latch plate in the full-size vehicle requires positioning it

at a very specific angle to the buckle so that it would catch.

Many older participants had difficulty finding this angle and

voiced their frustrations.

Participantshadmixedfeelings aboutthe aftermarketdevices.

When comparing the belt extender and the original system in

the compact vehicle, more than half the participants indicated

that the presence of the extender improved both the comfort

and usability of the seat belt. As for the shoulder pad, some

participants felt that it added comfort, but it got in the way

when they were trying to operate the system, while others

simply mentioned that it was too thick and it did not add any

comfort. The plastic loop was found to be helpful for many

of the participants in locating, reaching for, and pulling the

shoulder belt toward them. However, the plastic loop got in

the way when participants tried to buckle or complete other

maneuvers. Caution is necessary when interpreting the ratings and perceptions about the aftermarket devices since they

were confounded with the vehicle type they were tested in.

Each aftermarket device was not tested in each vehicle type.

Recommendations

There are a number of methods that may be used to increase

seat belt use among older adults. In consulting with experts

and examining existing data and literature, a number of key

research gaps and recommendations for future studies were

identified. Improved vehicle designs that willresult in higher

rates of seat belt use by allowing for more comfortable access

and fit should be explored. In addition, research that will

examine the seat belt use patterns of older adults or target

populations within the older adult community is needed to

forecast future scenarios and develop additional programs.

How to Order

For	a	copy	of	Occupant Protection Issues Among Older Drivers and Passengers	(Vol.	1,	Final	Report,	66	pages	and	Vol.	2,	

Appendices,	145	pages)	prepared	by	Westat,	Inc.,	write	to	the	

Office	of	Behavioral	Safety	Research,	NHTSA,	NTI-130,	1200	

New	Jersey	Avenue	SE.,	Washington,	DC	20590,	or	send	a	fax	

to	202-366-7394,	or	download	from	www.nhtsa.dot.gov.	Alan	

Block was the project manager for this study.

TRAFFIC TECH is a publication to disseminate information about

traffic safety programs, including evaluations, innovative programs, and new publications. Feel free to copy it as you wish. If you

would like to receive a copy, contact Patricia Ellison-Potter, Ph.D.,

Editor, fax 202-366-7394, e-mail: traffic.tech@dot.gov.

1200 New Jersey Avenue SE., NTI-130

Washington, DC 20590