Seat Belts and Child Restraints
Abundant research has shown that correctly using appropriate child restraints or seat belts is the single most effective way to save lives and reduce injuries in crashes. Lap and shoulder combination seat belts, when used, reduce the risk of fatal injury to front-seat passenger car occupants by 45% and the risk of moderate-to-critical injury by 50% (Kahane, 2015). For light-truck occupants, seat belts reduce the risk of fatal injury by 60% and moderate-to-critical injury by 65%.
NHTSA estimates that correctly used child restraints are even more effective than seat belts in reducing fatalities to children. Child restraints reduce fatalities by 71% for infants younger than 1 year old and by 54% for children 1 to 4 years old in passenger cars. In light trucks the fatality reductions are 58% for infants and 59% for children 1 to 4 years old (NCSA, 1996; Kahane, 2015). In addition, research conducted by the Partners for Child Passenger Safety Program at the Children’s Hospital of Philadelphia found that belt-positioning booster seats reduce the risk of injury to children 4 to 8 years in crashes by 45% when compared to the effectiveness of seat belts alone (Arbogast et al., 2009). However, unrestrained children continue to be overrepresented in motor vehicle fatalities, which indicates that additional lives can be saved by increasing restraint use among children (Sauber-Schatz et al., 2014).
Trends. The challenge is to convince all passenger vehicle occupants to buckle up. Current data show that observed daytime seat belt use nationwide was 90.7% in 2019 for adult drivers and right-front seat passengers combined (NCSA, 2019). There was no significant difference in use from 2018 (89.6%) to 2019 (90.7%). In 2019 seat belt use was over 90% in 26 States, the District of Columbia, and two U.S. Territories, with 4 States, the District of Columbia, and Guam achieving belt use rates higher than 95% (California, 96.0%, Georgia, 95.9%; Hawaii, 97.1%; Oregon, 95.7%; District of Columbia, 95.4%; and Guam, 96.9%) (NCSA, 2020a). Seat belt use, however, was less than 80% in 4 States (New Hampshire, 70.7%; Nebraska, 79.7%; South Dakota, 75.2%; and Wyoming, 78.3%) and the U.S. Virgin Islands (71.1%). Nationally, seat belt use has increased dramatically since seat belt use laws went into effect in the early 1980s (Hedlund et al., 2008; Li & Pickrell, 2018a). The National seat belt use rate has been trending upwards over the past two decades, rising 20 percentage points since 2000 (Enriquez & Pickrell, 2019; NCSA, 2019).
Sources: Enriquez & Pickrell (2019); NCSA, 2019
In general, overall restraint use for children is higher than what is demonstrated in the adult population, particularly among the youngest children. In 2017 restraint use for children less than 13 years old was 90.1% (Li & Pickrell, 2018b). Restraint use ranged from 97.9% for infants under 1 year old, to 86.5% for children 8 to 12. In general, child restraint usage rates decline as children age.
*Restraint use rates do not indicate correct use.
Source: Li and Pickrell (2018b)
However, restraint use for children is more complicated than simply “restrained versus unrestrained.” In addition to overall restraint use, it is also important to consider correct restraint use. The current NHTSA recommendations include keeping children rear-facing until the rear-facing height or weight limits of the car seat are outgrown, then forward-facing with a harness until the harness is outgrown by height or weight, and then booster seat use until the seat belt fits properly on its own (NHTSA, 2014a).
The 2017 National Survey of the Use of Booster Seats (Li & Pickrell, 2018b) details the observed restraint use for children under 1, 1 to 3, 4 to 7, and 8 to 12. There were some indications of premature transition to restraint types that are not appropriate for children’s age, height, and weight. In 2017 there were 92.1% of children under 1 observed in the appropriate rear-facing seats, up from 87.4% in 2015. Rear-facing and eventually forward-facing car seats are appropriate for children 1 to 3. The 2017 NSUBS found that 85.1% of children 1 to 3 used the appropriate restraint, compared to 77.0% in 2015, and 68.5% of children 4 to 7 were restrained using the appropriate forward-facing car seat or booster seat, which is up from 62.4% in 2015. Children 8 to 12 should use a booster seat until a seat belt fits properly. Of children 8 to 12 there were 85.4% appropriately restrained, compared to 83% in 2015. Child restraint use varies by race and ethnicity. Across children younger than 13 years old, White Non-Hispanics had the highest restraint use for infants birth to 12 months (99.4%) and White Non-Hispanic and Asian Non-Hispanic children had the highest restraint use for children 1 to 3 (98.1% and 98.6%, respectively) and children 8 to 12 (91.1% and 90.7%, respectively). Asian Non-Hispanic children had the highest restraint use for children 4 to 7 (99.8%). Non-Hispanic Black children had the lowest restraint use rates (birth to 12 months, 93.0%; 1 to 3, 86.8%, 4 to 7, 75.8%; 8 to 12, 79.9%).
Despite high observed belt use rates, many unrestrained people die in crashes each year. In 2018 there were 22,697 passenger vehicle occupants killed in crashes (NCSA, 2020b). Of these, where restraint use was known, 47% were unrestrained. Of the 736 children in 2018 under 15 who died in passenger vehicles, 35% were unrestrained.
History of Occupant Restraint Laws. All new passenger cars had some form of seat belts beginning with lap belts in 1964, shoulder belts in 1968, and integrated lap and shoulder belts in 1974 (Automobile Coalition for Traffic Safety [ACTS], 2001). However, few occupants used the belts. The first widespread survey completed in 19 cities in 1982, observed 11% belt use for drivers and front-seat passengers (Williams & Wells, 2004). This survey became the benchmark for tracking belt use nationally, until the National Occupant Protection Use Survey (NOPUS) began in 1994.
New York enacted the first statewide seat belt use law in 1984 with other States soon following. Evaluations of the first seat belt laws found that seat belt use increased following implementation of the law from baseline levels of about 15% to 20% to post-law use rates of about 50% (Nichols & Ledingham, 2008). Florida implemented a primary seat belt law in 2009. An evaluation of the law found observed seat belt use to increase by 4.3 percentage points from 80.9% to 85.2% (Nichols et al., 2012). Looking at law evaluations it appears that the relative effectiveness of implementing a primary law decreases as baseline seat belt use rates increase. As of June 2019 all States except New Hampshire require adult passenger vehicle drivers and front seat occupants to wear seat belts and 30 States and the District of Columbia also require seat belts for all rear seat passengers (GHSA, 2019a). Thirty-four States and the District of Columbia have primary enforcement seat belt use laws that permit LEOs to stop and cite a violator independent of any other traffic violation. Fifteen States have secondary enforcement laws that allow LEOs to cite violators only after they first have been stopped for some other traffic violation.
From 1978 to 1985 every State and the District of Columbia passed laws requiring child restraints for young child passengers (Kahane, 1986), and most of these laws have since been amended and strengthened to include more children and to close loopholes and exemptions. Still, great variation exists on the requirements and ages covered by State child restraint laws. See IIHS (2019a) and GHSA (2019b) for a summary of State law requirements.
For more information on the history of seat belt systems, seat belt use laws, enforcement programs, and seat belt use trends, see Kahane (2015), ACTS (2001), Solomon et al. (2004), Milano et al. (2004), NHTSA (2003), Williams and Wells (2004), and Hedlund et al. (2008). For a comprehensive summary on facts about child restraint use, see Dunn et al. (2016).