Traffic Safety Facts

Traffic Tech – Technology Transfer Series

Number 337 December 2007

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

National Highway Traffic Safety Administration

There	 is	 greatly	 increased	 crash	 risk	 when	 teenage	 drivers	

transport	passengers,	and	the	more	passengers,	the	greater	

the	 risk.	 Risk	 increases	 with	 one,	 two,	 or	 three	 or	 more	

passengers,	such	that	when	there	are	multiple	passengers	in	

the	vehicle,	crash	risk	is	3	to	5	times	greater	than	when	driving	

alone.	Passenger	presence	is	associated	with	increased	crash	

risk	for	both	male	and	female	teen	drivers;	risk	is	greater	for	

younger	teens	age	16	and	17	than	for	older	teen	drivers.	The	

increased	risk	with	passengers	has	been	found	for	all	types	of	

crashes:	property	damage,	nonfatal	injury,	and	fatal.

NHTSA	 contracted	 with	 Preusser	 Research	 Group	 (PRG)	

to	evaluate	the	passenger	restriction	components	of	several	

graduated	 driver	 licensing	 (GDL)	 laws	 on	 safe	 driving	

practices,	and	teen	crashes	and	fatalities.	PRG	also	assessed	

compliance	with	and	enforcement	of	the	passenger	restriction	

of	a	GDL	law	among	teen	drivers,	parents	of	teen	drivers,	

and	law	enforcement	personnel.

Crash Analyses

Selected	 study	 States	 were	 California,	 Massachusetts,	 and	

Virginia.	Each	State	was	paired	with	a	matching	comparison	

State	(Arizona	for	California,	Connecticut	for	Massachusetts,	

and	Maryland	for	Virginia)	to	help	control	for	confounding	

variables.	Time	series	analyses	were	run	on	crash	data	from	

these	States.	

Figure 1. Crash Involvement/1K Population for 16-Year-Old 

Drivers

The	 crash	 analyses	 support	 the	 contention	 that	 passenger	

restrictions	 reduce	 crashes	 among	 16-year-old	 drivers.	

Increases	in	other	types	of	crashes	or	an	increase	in	overall	

injuries	 does	 not	 appear	 to	 offset	 this	 decrease.	 Results	

indicate	that	in	California	there	are,	on	average,	740	fewer	

16-year-old	 drivers	 involved	 in	 crashes	 each	 year.	 In	

Massachusetts,	 the	 average	 annual	 reduction	 is	 173	 and	

in	 Virginia	 it	 is	 454.	 Further	 analyses	 revealed	 that	 the	

decreased	 teen	 crash	 rates	 were	 not	 part	 of	 a	 larger	 trend	

of	decreasing	crash	rates	among	all	drivers,	and	that	injury	

crashes	involving	more	than	one	passenger	under	18	in	two	

of	the	States	(MA	and	VA)	actually	decreased	among	16-yearold	drivers.

Focus Groups

Nine	focus	groups	were	conducted	in	each	of	the	three	States	

for	this	study	(California,	Massachusetts,	and	Virginia)	with	

teen	 drivers,	 parents	 of	 teen	 drivers,	 and	 law	 enforcement	

officers.	

Parents

Nearly	all	parents	recognized	that	teen	passengers	increase	

the	risk	of	crashes	and	injuries	among	newly	licensed	teen	

drivers.	As	a	result,	many	parents	imposed	some	rules	and	

restrictions,	allowing	their	newly	licensed	sons	or	daughters	

to	drive	under	certain	circumstances.	Usually	they	imposed	a	

curfew,	and	often	a	passenger	restriction.	A	surprisingly	large	

number	of	the	participating	families	had	written	parent/teen	

behavioral	contracts	regulating	driving	for	a	period	of	time	

after	licensure.	

Many	parents	had	ambivalent	attitudes	towards	GDL.	Most	

recognized	the	need	for	such	laws,	but	many	felt	the	laws	

were	unfair	to	their	own	children	because	they	perceived	their	

children	 as	 responsible	 and	 capable	 drivers.	 Some	 parents	

liked	 the	 GDL	 laws	 because	 they	 would	 have	 imposed	

restrictions	anyway,	and	the	law	saved	them	the	trouble	of	

negotiating	restrictions	with	their	teen	drivers.

All	parents	were	aware	that	there	were	curfew	and	passenger	

restrictions,	although	many	were	unsure	or	mistaken	about	

the	details	of	their	State’s	law.	The	perceived	benefits	of	the	

passenger	restrictions	were	that	they	reduce	distractions	and	

Passenger Restrictions in Graduated Driver 

Licensing Programs Crash Involvement / 1K Population

0

0.2

0.4

0.6

0.8

1.0

1.2

1.4

1.6

CA MA VA

State

1.07

0.88

1.41

0.85

0.61

1.1

Pre-Law

Post-Law
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	202-366-7096,	e-mail:	traffic.tech@dot.gov.

eliminate	peer	pressure	to	engage	in	risky	driving	behavior.	

Two	major	criticisms	of	passenger	restrictions	included	the	

fact	that	they	were	not	routinely	enforced	by	law	enforcement	

and	parents	felt	that	many	of	their	children’s	friends	paid	no	

attention	to	it.	Few	parents	believed	that	the	teen	passenger	

restrictions	are	vigorously	enforced,	even	in	Massachusetts,	

where	non-compliance	is	a	primary	violation.	Usually,	parents	

restricted	their	teens	from	carrying	passengers	whom	they	

do	not	know	or	particular	friends	they	had	reason	to	believe	

would	be	a	bad	influence,	but	many	permitted	their	children	

to	violate	the	law	when	they	felt	the	risk	was	acceptable.	Very	

few	parents	monitored	their	children’s	compliance	with	the	

State’s	legal	passenger	restrictions.

Teens

Teens	 generally	 agreed	 that	 driving	 with	 teen	 passengers	

in	 the	 car	 increases	 the	 risk	 of	 crashes	 and	 injured.	 While	

most	teens	did	not	like	having	parentally	imposed	rules	and	

restrictions	on	their	driving,	most	teens	had	some	rules	and	

restrictions,	and	were	resigned	to	accepting	them.

Teens	 were	 more	 knowledgeable	 about	 the	 GDL	 laws	 in	

their	State	than	parents	were,	but	many	had	misconceptions	

(e.g.,	 timeframes	 for	 nighttime	 restrictions,	 length	 of	

time	 passenger	 restrictions	 are	 in	 effect,	 etc.).	 While	

acknowledging	 the	 benefits	 of	 teen	 passenger	 restrictions,	

teens	 expressed	 more	 objections	 than	 parents	 did	 (e.g.,	

inconvenient,	 wasteful	 of	 gasoline,	 etc.).	 Compared	 to	

parents,	 teens	 were	 somewhat	 more	 likely	 to	 believe	 that	

police	 were	 enforcing	 the	 passenger	 restriction,	 but	 most	

perceived	the	likelihood	of	getting	a	ticket	as	very	low.	Some	

teens	knew	that	non-compliance	was	a	secondary	violation	

in	their	State,	but	many	did	not.	Most	teens	knew	that	many	

of	their	friends	violated	the	restriction	all	the	time	and	had	

never	been	ticketed	for	it.

Very	 few	 teens	 complied	 with	 the	 passenger	 restriction	 all	

of	the	time.	Some	violated	the	restriction	with	their	parents’	

permission	and	others	avoided	situations	where	their	parents	

would	know	about	it.	Some	attempted	to	avoid	tickets	by	not	

carrying	passengers	in	view	of	police	at	school	and	obeying	

traffic	laws	to	avoid	being	stopped.

Law Enforcement

Police	 in	 all	 three	 States	 acknowledged	 that	 carrying	 teen	

passengers	 increases	 the	 risk	 of	 crashes	 and	 injury	 among	

young	 drivers.	 Generally,	 police	 officers	 were	 in	 favor	 of	

GDL	and	felt	that	the	passenger	restriction	is	more	important	

than	 the	 curfew	 from	 a	 highway	 safety	 viewpoint.	 All	

the	 participating	 law	 enforcement	 agencies	 had	 outreach	

programs	to	educate	new	teen	drivers	and	parent	groups	on	

safe	driving	practices,	including	the	passenger	restriction.

Police	 in	 all	 three	 States	 said	 that	 their	 State’s	 teen	

passenger	 restrictions	 were	 difficult	 to	 enforce.	 Although	

noncompliance	 with	 the	 passenger	 restriction	 is	 a	 primary	

violation	in	Massachusetts,	police	make	few	primary	stops	

because	 it	 is	 difficult	 to	 judge	 the	 age	 of	 occupants	 in	 a	

moving	 vehicle.	 Even	 after	 a	 stop	 for	 another	 violation,	

passenger	restriction	citations	are	difficult	because	a	registry	

check	is	required	to	determine	if	the	driver	has	been	licensed	

less	 than	 six	 months,	 and	 passengers	 are	 not	 required	 to	

produce	 identification	 without	 probable	 cause	 (MA	 only).	

Virginia	 traffic	 patrol	 officers	 reported	 that	 they	 cite	 every	

passenger	restriction	violation	they	can	when	making	a	stop.	

While	Virginia	officers	can	determine	whether	the	driver	is	

restricted	from	information	shown	on	the	license,	they	have	

some	 difficulty	 in	 determining	 the	 age	 and	 relationship	 of	

the	passengers	before	writing	a	citation.	Officers	complained	

about	 the	 sibling	 exemption.	 California	 officers	 had	 no	

complaints	about	difficulties	in	writing	passenger	restriction	

citations	after	making	a	stop	because	restricted	licenses	are	

clearly	marked	and	exceptions	require	prior	authorization	by	

the	DMV.

Police	 in	 all	 States	 recognized	 that	 outside	 of	 the	 traffic	

enforcement	 units,	 few	 officers	 wrote	 many	 passenger	

restriction	 citations.	 Other	 officers	 had	 higher	 priorities	

and,	when	making	traffic	stops,	usually	only	wrote	tickets	

for	 the	 stopping	 violations.	 Factors	 that	 discouraged	 law	

enforcement	officers	from	citing	violations	include	sympathy	

for	the	violators	and	lenient	treatment	of	juvenile	violators	

by	 the	 courts.	 None	 of	 the	 departments	 have	 conducted	

any	 special	 emphasis	 patrols	 or	 training	 on	 passenger	

restrictions,	although	the	Fairfax	County,	Virginia,	police	do	

have	 special	 traffic	 enforcement	 patrols	 around	 schools	 in	

the	fall	and	spring.

How to Order

To	order	Passenger Restrictions in Graduated Driver Licensing 

Programs (50	pages	plus	appendices)	prepared	by	Preusser	

Research	 Group,	 write	 to	 the	 Office	 of	 Behavioral	 Safety	

Research,	 NHTSA,	 NTI-130,	 1200	 New	 Jersey	Avenue	 SE.,	

Washington,	DC	20590,	fax	202-366-7096,	or	download	from	

www.nhtsa.dot.gov.	Patty	Ellison-Potter,	Ph.D.,	was	the	Task	

Order	Manager	for	this	project.

1200	New	Jersey	Avenue	SE.,	NTI-130

Washington,	DC	20590