Traffic Safety Facts

Traffic Tech – Technology Transfer Series

Number 363 February 2009

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

National Highway Traffic Safety Administration

Background

The	 purpose	 of	 this	 project	 was	 to	 improve	 upon	 existing	self-screening	instruments	for	older	drivers	by	focusing	entirely	on	health	concerns	that	affect	driving—that	

is,	the	symptoms	that	people	experience	due	to	medical	

conditions,	 the	 medications	 used	 to	 treat	 them,	 and	 the	

general	 aging	 process—rather	 than	 the	 medical	 conditions	 or	 medications	 themselves.	 The	 project	 created	 an	

easy-to-use	 self-screening	 instrument	 for	 older	 drivers	

that	would	provide	several	types	of	individualized	feedback	including	information	to	increase	general	awareness	

and	self-awareness	relative	to	declines	in	driving-related	

abilities,	as	well	as	recommendations	for:

n	 behavioral	 changes	 or	 safety	 tips	 to	 maintain	 safe	

	driving	(e.g.,	avoiding	driving	at	night,	taking	a	driver	

refresher	course,	planning	a	trip	in	advance,	and	writing	down	the	route);

n	 further	 evaluation	 from	 a	 physician	 or	 other	 health	

	professional;	and	

n	 vehicle	modifications	to	help	compensate	for	drivingrelated	declines.	

Method

Project	 activities	 included	 a	 literature	 review,	 an	 expert	

panel	 to	 discuss	 how	 health-concern	 severity	 relates	 to	

driving	skills	and	to	identify	appropriate	accommodations	

for	declines	in	these	skills,	preliminary	development	of	a	

self-screening	 instrument	 guided	 by	 focus	 group	 input	

from	older	adults,	and	an	evaluation/validation	study.	

The	literature	review	had	two	parts.	The	focus	of	the	first	

part	 was	 to	 better	 understand	 the	 health	 concerns	 that	

might	influence	driving.	The	objective	was	to	develop	a	

list	of	health	concerns	and	to	estimate	the	severity	of	these	

concerns	 and	 the	 conditions	 under	 which	 each	 concern	

would	 most	 likely	 occur.	 The	 second	 part	 was	 to	 identify	critical	driving	skills	and	determine	what	capabilities	

would	be	required	to	perform	each	skill	adequately.

A	panel	of	subject	matter	experts	then	was	convened	to:	(1)	

help	finalize	the	lists	of	health	concerns	and	critical	driving	

skills	to	be	included	in	the	self-screening	instrument;	(2)	

discuss	how	severity	levels	of	the	health	concerns	influence	critical	driving	skills;	and	(3)	consider	the	content	of	

the	self-screening	instrument’s	feedback	recommendations	

for	 behavioral	 changes,	 further	 evaluation,	 and	 vehicle	

modifications.	Panel	members	were	selected	from	a	variety	 of	 backgrounds	 with	 expertise	 in	 geriatrics,	 driving	

task	analysis,	highway	safety,	and	vehicle	modifications.	

Ensuing	 development	 of	 the	 self-screening	 instrument	

involved	five	tasks.	The	first	was	a	series	of	brainstorming	sessions	by	project	team	members	that	focused	mainly	

on	comparing	the	merits	of	a	paper-and-pencil	instrument	

versus	an	electronic	instrument.	Team	members	decided	

that	 an	 electronic	 (Web	 site)	 format	 was	 superior.	 Next	

was	 a	 set	 of	 focus	 groups	 with	 drivers	 65	 and	 older	 to	

obtain	reaction	to	potential	Web	site	issues	and	features.	

The	third	task	was	to	develop	the	draft	Web	site	for	the	

instrument.	 Based	 on	 earlier	 project	 activities,	 27	 health	

concerns	 and	 15	 critical	 driving	 skills	 were	 chosen	 for	

inclusion	in	the	instrument.	Task	four	was	to	develop	the	

feedback	that	would	be	provided	to	users	based	on	their	

individual	responses	to	the	questions	in	the	self-screening	

instrument.	The	final	task	was	to	present	and	discuss	the	

instrument	in	a	focus	group	with	older	adults.	This	group	

discussion	was	to	ensure	that	the	questions	and	feedback	

were	appropriate	and	understandable,	to	gather	feedback	

on	the	Web	site	format	and	style,	and	to	determine	how	

users	would	interact	with	the	Web	site.

The	 evaluation	 study	 assessed	 whether	 the	 instrument	

increased	self-awareness	of	age-related	declines	in	driving	 abilities	 and	 was	 perceived	 as	 useful.	 It	 involved	

obtaining	 feedback	 from	 study	 subjects	 after	 they	 had	

completed	 the	 self-screening	 instrument.	 The	 validation	

study	assessed	how	accurately	the	instrument	identified	

health	concerns	and	potential	driving	difficulties.	It	compared	subjects’	scores	on	the	self-screening	instrument	to	

results	from	an	on-road	driving	assessment	and	a	series	

of	clinical	tests	to	evaluate	cognitive,	visual,	and	psychomotor	abilities	related	to	driving.	Both	the	clinical	evaluation	and	on-road	driving	assessment	were	administered	

through	an	established	driving	assessment	program	operDevelopment of a Self-Screening Instrument for 

Older Drivers Based on Health Concerns
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	Dr.	Angela	Eichelberger,	

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

1200	New	Jersey	Avenue	SE.,	NTI-130

Washington,	DC	20590

ated	by	the	University	of	Michigan	and	managed	by	an	

occupational	therapist.	

Evaluation and Validation Results

Sixty-eight	older	adults	participated	in	the	evaluation	and	

validation	 study.	 After	 using	 the	 self-screening	 instrument,	 the	 68	 subjects	 provided	 feedback	 in	 three	 areas:	

self-awareness,	 intentions	 to	 make	 behavioral	 changes,	

and	 perceived	 utility	 of	 the	 instrument.	 Regarding	 selfawareness,	76	percent	of	subjects	thought	the	self-screening	 instrument	 made	 them	 more	 aware	 of	 changes	 that	

can	affect	driving,	94	percent	thought	it	served	as	a	useful	

reminder	of	things	they	already	knew,	and	38	percent	discovered	changes	in	themselves	of	which	they	were	previously	unaware.	

Many	 also	 expressed	 intentions	 to	 make	 behavioral	

changes	as	a	result	of	completing	the	instrument.	Fortytwo	 percent	 of	 subjects	 indicated	 that	 after	 completing	

the	 self-screening	 instrument	 they	 were	 going	 to	 make	

changes	in	the	way	they	drove,	and	33	percent	indicated	

they	were	now	thinking	about	taking	a	driving	refresher	

course.	 More	 than	 one-half	 of	 subjects	 (53%)	 indicated	

that	they	were	now	more	likely	to	discuss	health	concerns	

they	were	experiencing	with	a	doctor.	Few	subjects	(11%),	

however,	reported	considering	vehicle	modifications.

As	 to	 perceived	 utility,	 77	 percent	 of	 subjects	 indicated	

that	they	would	use	the	Web-based	instrument	again	in	

the	 future	 if	 it	 was	 available,	 92	 percent	 would	 recommend	it	to	older	friends	or	family	members,	and	94	percent	thought	it	would	help	older	adults	talk	about	driving	

concerns	with	their	families.	Overall,	37	percent	of	subjects	

rated	the	instrument	extremely	useful;	48	percent	rated	it	

moderately	useful.

The	validation	study	was	designed	to	assess	whether	the	

self-screening	instrument	accurately	identified	problems	

with	 driving,	 based	 on	 health	 concerns.	 Subjects’	 scores	

on	the	self-screening	instrument	were	compared	to	their	

scores	on	the	on-road	driving	assessment,	and	the	clinical	

evaluation.	Overall	scores	on	the	self-screening	instrument	

were	 significantly	 correlated	 with	 driving	 performance	

measured	 on	 the	 road;	 that	 is,	 those	 drivers	 who	 had	 a	

greater	 number	 of	 health	 concerns	 as	 identified	 by	 the	

instrument	also	tended	to	have	poorer	observed	driving	

performance	 (Table	 1).	 Significant	 correlations	 between	

instrument	 and	 on-road	 driving	 scores	 were	 also	 found	

for	the	subgroup	of	drivers	75	and	older.	Scores	from	the	

instrument	and	on-road	assessment	were	not	significantly	

correlated	for	other	subgroups.	Subjects’	scores	on	the	selfscreening	 instrument	 were	 also	 significantly	 correlated	

with	the	clinical	evaluation	performed	by	a	certified	driving	rehabilitation	specialist,	due	primarily	to	adults	75	and	

older,	and	women.	Overall,	though	several	correlations	in	

the	study	were	statistically	significant,	they	accounted	for	

a	rather	modest	amount	of	total	variance.

Table 1: Correlations Between Self-Screening InstrumentIdentified Health Concerns, On-Road Driving Performance, 

And Clinical Evaluation

Age 

Overall Men Women 65-74 Age 75+

Instrument versus 

On-Road Driving -.26* -.34 -.22 -.02 -.44#

Instrument versus 

Clinical Evaluation .26* .30 .35* -.07 .54#

* Significant at the p<.05 level # Significant at the p<.01 level

Recommendations

The	evaluation/validation	study	showed	the	self-screening	instrument	to	have	positive	value.	Subjects	considered	

it	useful,	and	scores	derived	on	the	instrument	were	significantly	correlated	with	actual	driving	performance	and	

clinical	evaluation	for	older	adults	75	and	older.	It	should	

be	 noted	 that	 the	 instrument	 is	 intended	 as	 a	 first-tier	

screening	tool	to	determine	gross	impairment	rather	than	

fitness	 to	 drive.	 Fitness	 to	 drive	 should	 be	 determined	

through	 second-tier	 screening	 that	 requires	 professional	

administration.	The	self-screening	instrument	does,	however,	 provide	 recommendations	 for	 seeking	 second-tier	

screening	where	appropriate.

How to Order

For	 a	 copy	 of Older Driver Self-Screening Based on 

Health Concerns (Vol.	1	Technical	Report,	26	pages,	and	

Vol.	 2	Appendices,	 78	 pages)	 prepared	 by	 The	 University	of	Michigan	Transportation	Research	Institute,	write	

to	 the	 Office	 of	 Behavioral	 Safety	 Research,	 NHTSA,	

NTI-130,	1200	New	Jersey	Avenue	SE.,	Washington,	DC	

20590,	 send	 a	 fax	 to	 202-366-7394,	 or	 download	 from	

www.nhtsa.gov.	Alan	Block	was	the	project	manager	for	

this	study.