Traffic Safety Facts

Traffic Tech – Technology Transfer Series

Number 359 February 2009

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

National Highway Traffic Safety Administration

Since	1975	motor	vehicle	crashes	have	been	the	leading	cause	

of	death	for	children	in	the	United	States.	The	most	effective	

strategy	for	preventing	injury	and	death	to	children	involved	

in	crashes	is	using	age-	and	size-appropriate	restraints.	TransAnalytics,	LLC,	completed	a	study	that	examined	the	factors	

that	relate	to	the	use	and	nonuse	of	booster	seats,	and	identified	strategies	to	improve	the	effectiveness	of	enhanced	child	

restraint	 laws	 that	 cover	 booster-seat-age	 children	 (booster	

seat	laws).	

Review of Changes in Booster Seat Laws

While	the	number	of	States	and	Territories	that	have	enacted	

booster	seat	provisions	has	increased	from	11	to	39	since	2000,	

wide	variations	in	age,	height,	and	weight	requirements	still	

exist.	 	 Several	 States	 have	 changed	 their	 age,	 height,	 and	

weight	 requirements	 to	 meet	 NHTSA’s	 best	 practices	 for	

booster-seat-age	children.	The	number	of	jurisdictions	with	

laws	that	cover	children	4	to	8	years	old	(currently	18	jurisdictions,	with	2	of	these	covering	children	up	to	age	9)	has	

more	 than	 quadrupled	 since	 2002.	 	 Within	 the	 same	 time	

period,	the	number	of	jurisdictions	with	laws	that	cover	children	who	weigh	up	to	80	pounds	has	increased	to	10	States.	

Unfortunately,	 more	 than	 half	 of	 the	 States	 with	 booster	

seat	law	provisions	are	still	operating	below	best	practices	

for	age.		In	2002	only	3	States	had	height	provisions	in	their	

booster	 seat	 laws.	 As	 of	 mid-2007,	 10	 States	 have	 height	

requirements	that	represent	best	practice	(up	to	57	inches).	

Four	other	States	have	height	requirements	that	fall	short	of	

best	practice	recommendations.		

Literature Review

A	review	of	recent	research	noted	differences	in	knowledge,	

attitudes,	 and	 perceptions	 between	 parents	 and	 caregivers	

who	use	booster	seats	and	those	who	do	not.		The	following	factors	were	associated	with	nonuse	of	booster	seats:	lack	

of	understanding	of	the	laws;	low	risk	perception;	permissive	parenting;	lack	of	understanding	of	the	safety	benefits	of	

booster	seats;	and	child	discomfort	or	resistance.	

Observational	studies	conducted	during	the	past	5	years	have	

reported	 varying	 percentages	 of	 4-	 to	 8-year-old	 children	

restrained	in	booster	seats;	however,	the	most	recent	NHTSA	

observational	 study	 (Glassbrenner	 and	 Ye,	 2007)	 found	 41	

percent	restrained	in	booster	seats,	17	percent	in	child	safety	

seats,	 and	 42	 percent	 either	 inadequately	 protected	 in	 seat	

belts	(33%)	or	completely	unrestrained	(9%).		

Effects of Upgrading Booster Seat Laws

Observations	of	child	passengers	age	4	to	8,	before	and	after	

Wisconsin	passed	its	booster	seat	law	in	2006,	showed	a	significant	increase	in	the	percentage	of	appropriately	retrained	

children	 following	 enactment	 of	 a	 booster	 seat	 law.	 	 Child	

safety	seat	and	booster	seat	use	in	this	age	group	increased	by	

9.1	percentage	points	in	Wisconsin,	from	48.6	percent	in	the	

pre-law	period	to	57.7	percent	in	the	post-law	period.		Similar	observations	in	a	comparison	State,	Michigan,	which	did	

not	have	booster	seat	provision	to	its	child	passenger	safety	

law,	showed	an	increase	of	5.9	percentage	points	during	the	

same	time	periods;	however,	the	increase	was	not	statistically	

significant.		

Table 1. Restraint Use for Booster-Seat-Age Children

Wisconsin Michigan

Pre Post Pre Post 

N=407 N=355 N=472 N=465

Seat belt 30.7% 21.1% 45.6% 35.7%

CSS 8.6% 11.8% 3.0% 7.3%

Booster 40.0% 45.9% 38.6% 40.2%

Unrestrained 20.6% 21.1% 12.9% 16.8%

Total 100.0% 100.0% 100.0% 100.0%

Overall,	booster	seat	use	increased	5.9	percentage	points	in	

Wisconsin	and	1.6	percentage	points	in	Michigan	during	this	

period.

Law Enforcement Attitudes

In	2006	focus	groups	with	small	groups	of	10	law	enforcement	

officers	held	in	Chicago,	Pittsburgh,	Richmond,	and	Sacramento	identified	a	number	of	barriers	to	enforcing	booster	

seat	laws.	These	include:	a	lack	of	commitment	by	top	management	(e.g.,	police	chiefs)	to	enforce	these	laws;	a	shortage	

of	 law	 enforcement	 officers	 knowledgeable	 on	 the	 subject	

of	child	safety	seats	and	booster	seats;	lack	of	resources	to	

Identifying Strategies to Improve the 

Effectiveness of Booster Seat Laws 
enforce	booster	seat	laws;	booster	seat	laws	that	are	secondary	violations;	and	lenient	judges	who	dismiss	booster	seat	

citations.	 Law	 enforcement	 officers	 who	 identified	 reasons	

for	 parent	 and	 caregiver	 nonuse	 of	 booster	 seats	 cited	 the	

public’s	ignorance	of	the	child	restraint	laws,	and	the	public’s	

failure	to	recognize	the	degree	of	risk	to	unrestrained	or	inappropriately	restrained	children.			

Parent and Caregiver Attitudes

Groups	of	10	to	12	parents	and	caregivers	who	attended	focus	

groups	in	Chicago,	Pittsburgh,	Richmond,	and	Sacramento	

identified	 several	 barriers	 to	 booster	 seat	 use,	 which	 they	

attributed	to	ignorance	of	safety	issues	and	laws,	parenting	

styles,	 and	 lack	 of	 enforcement.	 Specifically,	 many	 parents	

and	caregivers	lack	an	understanding	of	(a)	child	occupant	

protection	laws,	(b)	the	risks	involved	to	their	children	when	

they	are	not	appropriately	restrained,	and	(c)	the	safety	benefits	offered	by	booster	seats.	In	addition,	many	parents	said	

they	do	not	enforce	discipline	when	children	resist	using	the	

seats.	Because	of	the	low	perceived	threat	of	getting	a	ticket	

for	booster	seat	violations,	parents	have	not	been	compelled	

to	change	their	habits.

Strategies 

The	following	list	of	strategies	to	improve	the	effectiveness	

of	booster	seat	laws	was	developed	from	information	generated	 from	 the	 previous	 task	 activities.	 Although	 education,	 enforcement,	 and	 legislation	 are	 strategies	 commonly	

practiced,	they	continue	to	be	valid	approaches	to	increase	

booster	seat	use.	

Education

It	is	important	to	educate	those	parents	and	caregivers	who	

do	not	use,	use	inconsistently,	or	use	booster	seats	inappropriately,	based	on	age	and	height	the	best	practices	identified	

by	NHTSA.	The	assumption	is	that	once	parents	and	caregivers	know	how,	when,	and	why	they	should	use	booster	

seats,	 they	 will	 properly	 secure	 their	 booster-age	 children.	

Each	year,	new	children	reach	booster	seat	age,	so	the	need	

to	educate	parents	and	caregivers	remains	constant.	Efforts	

to	 educate	 parents	 and	 caregivers	 need	 to	 be	 periodically	

refreshed	to	address	changing	sensibilities,	changes	in	law,	

and	 updated	 research	 about	 child	 passenger	 safety.	 Many	

people	can	educate	parents	and	caregivers	about	booster	seat	

use.	 These	 include	 child	 safety	 advocates,	 car	 seat	 technicians,	law	enforcement	officers,	emergency	medical	service	

technicians	and	health	care	providers,	as	well	as	child	safety	

seat	and	car	manufacturers	and	retailers.	Topics	that	should	

be	taught	include:			

 The	best	practices	for	securing	children	in	age-	and	sizeappropriate	restraints;	

 The	risks	caused	by	inappropriate	restraint	use;	and		

 Resources	to	find	booster	seats	in	low-income	communities.	

Enforcement 

Effective	enforcement	of	booster	seat	laws	requires	coordination	between	several	sectors	of	the	enforcement	community.	

The	 following	 strategies	 are	 interdependent,	 and	 address	

five	key	points:	

 Motivate law enforcement leadership to enforce 

occupant restraint	laws.

 Train law enforcement officers on child passenger 

safety issues.

 Strictly	enforce	laws	pertaining	to	child	passenger	safety.

 Train judges about child passenger safety issues to 

uphold citations.	

 Collect appropriate enforcement data to analyze 

and refine booster	seat	law	enforcement	efforts.

Legislation

A	final	strategy	is	to	promote	“stronger”	booster	seat	laws	

(e.g.,	without	unnecessary	exemptions,	and	conforming	with	

best	practice	recommendations)	and	primary	enforcement	of	

seat	belt	laws.		This	study	showed	that	passage	of	a	booster	

seat	law	increases	child	safety	seat	and	booster	seat	use.			To	

strengthen	 these	 laws,	 there	 is	 a	 need	 to	 increase	 the	 age,	

weight,	and	height	limits	in	the	booster	seat	provisions	of	the	

child	restraint	law	in	many	States	(e.g.,	at	least	to	8	years	old	

and	4‘9”	tall).		The	study	found	that	there	are	some	misperceptions	by	parents	and	caregivers	that	the	State	law	represents	the	best	practice;	therefore,	if	they	follow	the	law,	their	

children	are	safely	secured.		However,	the	booster	seat	laws	

do	not	represent	best	practice	in	all	States.	

How to Order

To	 order Identifying Strategies to Improve the Effectiveness of 

Booster Seat Laws	 (59	 pages	 plus	 appendices),	 prepared	 by	

TransAnalytics,	LLC,	write	to	the	Office	of	Behavioral	Safety	

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

Washington,	DC	20590,	fax	202-366-7394,	or	download	from	

www.nhtsa.dot.gov.	John	Siegler,	Ph.D.,	was	the	Contracting	

Officer’s	Technical	Representative	for	this	project.

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