In the Fall of 2000, 21 percent more Young Adults (persons 16 – 24 years of age) were restrained by shoulder belts than were restrained in the Fall of 1998. These estimates were obtained through the National Occupant Protection Use Survey (NOPUS) which is conducted by the National Highway Traffic Safety Administrations (NHTSA) under the direction of its National Center for Statistics and Analysis (NCSA). Although this 12 percentage point increase in shoulder belt use by Young Adults was the only age group with a statistically significant change from 1998, estimates from the Fall 2000 NOPUS, which was conducted in September and October 2000, continued to reflect the upward trend in shoulder belt use rates that has occurred since the NOPUS was first conducted in 1994. This is the second in a series of Research Notes from NCSA presenting the results from the Fall 2000 NOPUS survey. NOPUS is composed of two separate studies: the moving traffic study, which provides information on overall shoulder belt use; and the controlled intersection study, which provides more detailed information about shoulder belt use by type of vehicle and person characteristics and child restraint use. This note presents results from the Controlled Intersection Study. The results from the Moving Traffic Study were released by NCSA in a Research Note dated February 2001, Observed Safety Belt Use Fall 2000 National Occupant Protection Use Survey. A third Research Note that will include more information on types of vehicles is being developed. Data collection for the controlled intersection study was conducted for 40 minutes at approximately 1200 randomly selected intersections with stop signs or traffic signals. Two observers recorded shoulder belt use for drivers and the right front seat passengers of passenger cars, vans, sport utility vehicles, and pickup trucks, the vehicle’s license plate number, and the age group, sex and race of the observed person. Age, sex, and race were based on the judgment of the observers. Child restraint information was collected for children under five years old in the front and second seats of the vehicle. Every day of the week and all daylight hours (8 a.m. to 6 p.m.) were covered by the study. Commercial and emergency vehicles were excluded. The NOPUS is a multi-stage, probability-based sample survey. Consequently, each estimate has been statistically weighted according to the sample design and is subject to sampling variability. Estimates in the following tables are shown with their sampling errors in parentheses. Adding and subtracting twice the sampling error from the estimate will produce an approximate 95 percent confidence interval. This means that one can be 95 percent confident that the true use rate lies within this interval. More information about the sample design and estimation procedures is available from the National Center for Statistics and Analysis. Restraint use was observed for 7,516 drivers and 2,354 passengers in passenger cars, 2,851 drivers and 985 passengers of vans and SUVs, and 1,908 drivers and 527 passengers in pickup trucks. Restraint use varied according to driver’s or passenger’s age group, sex, race, and type of area where the data were collected. Tables 1 and 2 compare observed rates from the 1994, 1996, 1998 and 2000 NOPUS Controlled Intersection Studies for selected characteristics. Tables 3 - 7 present detailed results from the 2000 study only. The age categories used in this Research Note, unless otherwise noted, are defined as follows: Infant - less than one year old; Toddler - 1 to 4 years; Youth - 5 to 15 years; Young Adult - 16 to 24 years; Adult - 25 to 69 years; and, Senior - over 69 years. Restraint use by specific vehicle type and available restraint system will be presented in a future Research Note. Observing child restraint use at randomly selected sites poses certain collection and estimation problems. Since only 8 percent of the resident population of the country are children under the age of 5, observing enough children in passenger vehicles to produce reliable estimates is difficult. During the controlled intersection collection, a total of 92 infants and 223 toddlers were observed. Consequently, estimates of child restraint use are subject to large sampling errors and should be interpreted with caution. For instance in Table 3, the margin of error on the estimate of 24 percent for Toddlers in passenger cars that were belted in the front seat is 23 percent. Therefore this estimate is unreliable. The Infant and Toddler categories are combined in Tables 2 and 7 due to the small number of observations. In addition to the significant increase in the use rate for Young Adults, Table 1 shows a 2 percentage point decrease in the restraint use rate for Infants and a 6 point decrease for Youth from 1998 to 2000. However these decreases are not statistically significant. Table 2 shows large increases in restraint use for children under 5 in several categories from 1998 to 2000. There was a 9 percentage point increase in suburban areas, a 15 point increase for front seat children, and a 20 point increase during the prime commuting hours. Each of these categories has exhibited substantial increases since 1996. The 22 point drop in rural areas is not statistically significant, and may have been caused by a small number of observations. Although it is safest for children under 5 to be placed in an age appropriate child safety seat in the rear seat of passenger vehicles, in the Controlled Intersection Study occupants in this age group (Infants and Toddlers) were counted as “restrained” if they were in a child safety seat or a shoulder belt (but not if in a lap belt) in either the front or rear seat. Table 3 shows that 3 percent of Infants and 45 percent of Toddlers were observed in shoulder belts and that at least 49 percent of Infants and 35 percent of Toddlers were in the front seat. At least 65 percent of Infants in passenger cars, and 50 percent of Toddlers in vans and SUVs were in the front seat. We do not give estimates by restraint type for pickups due to the small number of children under 5 observed in pickups. No attempt was made to measure child safety seat misuse. Tables 4-6 show the continuation of many patterns of belt use. Belt use continues to be higher in passenger cars (73 percent) and in vans and SUVs (74 percent) than in pickup trucks (60 percent), as shown in Table 4. In fact passengers in pickup trucks consistently exhibited the lowest use rates among all occupant and vehicle types. Belt use is higher among older occupants than younger (e.g. 76 percent for seniors versus 66 percent for youth). Use rates in rural areas (Table 5) were slightly lower, but not statistically different, than those in urban and suburban areas. However, pickup truck occupants have statistically higher belt use in cities (73 percent) than in suburban (45 percent) or rural areas (53 percent). Table 6 shows that there are no significant differences in belt use among races overall, but that use rates between the sexes are statistically different (77 percent for females versus 67 percent for males). Although it may be true that children under 5 are more likely to be restrained when their drivers are restrained or female, the results in Table 7 are not statistically significant. Similarly, there is no significant difference in restraint use of drivers among those with restrained children, unrestrained children, and no children.(A) This research note may be accessed by Internet users at: http://www.nhtsa.dot.gov/people/ncsa/ResearchNotes/809-318.pdf
Samenvatting