A systematic review of the effectiveness of policies that regulate booster seats among children aged 4 to 8.

Author(s): Uprajhiya, Ouimet, Nazif-Muoz,

Slidedeck Presentation:

Santosh CARSP 2022-05-23



Yearly more than 39,000 children under the age of 10 years old die in traffic crashes. A common factor among children killed or injured in motor vehicle traffic collisions is the absence of child restraint and/or booster seat use. Previous systematic reviews have assessed either the impact of policies regulating child restraints and child traffic outcomes in children below 4 years of age or the impact of interventions on booster seat use among 4- to 8-year-old children. No systematic reviews have analyzed the association between policies that regulate booster seats (PBS) and child traffic outcomes.


The primary objective of the present study is to systematically review studies exploring the associations between PBS and traffic child injuries and mortalities.


A systematic literature search of five databases (i.e., AMED, APA PsycInfo, CINAHL, MEDLINE, and SocINDEX) was conducted from January 1975 to November 2021 to retrieve relevant publications. Studies that had assessed the association between PBS and fatal and/or nonfatal injury in 4-to 8-year-old children were included. Keywords related to road traffic crashes and their consequences, child restraints, boosters, and legislations were used to make a search using proximity operators.


Among the 1965 identified articles, eight studies were selected for this review. All of the studies were conducted in high-income countries; around two-thirds in the United States. Overall, PBS were associated with a 5% to 21% reduction in fatal and nonfatal injuries among children aged 4 to 8 years. In the United States, PBS were also associated with an increase in booster seat use up to three-fold and rear seat ride by six percent.


While PBS were positively associated with a reduction in fatal and nonfatal injuries, results varied between studies. Different factors may be associated with these results. Along with PBS, the reviewed studies also included other interventions, such as public campaigns and manuals for rear booster seat use. Studies also suggest that the education-only measure is less effective to increase booster seat use among 4-to 8-year-old children. In comparison to education-only intervention, either distribution of booster seats and education in combined or incentive and education in combined can be more effective.


PBS may be associated with reductions in fatal and nonfatal injuries among children aged 4 to 8 years. However, other factors together with PBS may play a role. Finally, it should be noted that all the reviewed studies were conducted in high-income countries, suggesting the need for more research in low- and middle-income countries.