North Dakota’s rural roads provide vital social and commercial links for a widely dispersed population. The safety of these roadways is paramount in managing traffic assets to enhance the state’s liveability. Approximately two-thirds of the state’s travel, in vehicle-miles, takes place on rural roads that interconnect small communities and join the rural geography to interstates, principal state corridors, and urban centers (NDDOT). This level of rural driving is relatively high considering only about a third of the nation’s travel occurs on rural roads (U.S. DOT). From a safety perspective, this poses an inherent challenge because the risk for serious injury and death on rural roads is relatively high compared to the risk on urban roads (U.S. DOT 2005, U.S. DOT 2009a). In North Dakota, crash reports from 2010 to 2014 show that nearly 82% of fatal crashes and 89% of serious injury crashes — which includes those with fatal and disabling injuries — occurred on non-interstate rural roads (NDDOT 2015). With the understanding that seat belts are a relatively low-cost safety device, and are an easy means of primary protection for occupants in passenger vehicles, North Dakota has chosen to continue to measure seat belt use on non-interstate rural roads. Understanding tendencies and trends in seat belt use on these rural roads is essential to wise decisions regarding efforts to encourage seat belt use in the state. The U.S. Department of Transportation does work with states to measure seat belt use through the long-standing annual National Occupant Protection Use Survey (NOPUS). Results in this survey are a supplement to the NOPUS state-wide estimate which also includes urban and interstate travel that are heavily weighted in the final seat belt use estimate. Figure 1.1 provides some insight into seat belt use based on occupant reports for crashes by road type. Although not a perfect reflection of use on the road types, trends do offer some insight for the larger occupant population. Other perspective on the traffic crashes are offered in the seat belt use rates by occupant injury outcome and crash incidence trends. The crash incidence is categorized by the most serious injury outcome of a crash event to provide additional context regarding traffic activity. The observation study of the larger occupant population reported on in this study is a continuation of efforts to measure seat belt usage for all occupants on rural roads in North Dakota. The method used in the 2015 survey is a continuation of a survey initiated in 2009. As with the previous surveys, a direct observation method was used. A first step in administering the survey was to define a representative and realistic survey sample. The sampling was based on rural county populations and geographic representation of counties across four quadrants of the state. Counties were used as the boundaries for the initial selection stratum in the sample because population and other demographic information for counties are readily available. The quadrants were defined based on the North Dakota Health Department administration regions (Figure 2.1). Initially, stratified random sampling was conducted with rural counties that are not part of the NOPUS survey. Due to changes that occurred with the NOPUS method for the 2012 survey, the counties in the rural survey were selected to avoid duplication of counties between the surveys. The counties excluded from the annual state-wide seat belt survey comprise the state’s rural county geography for this project. The three highest population counties in the state-wide seat belt survey have approximately 62 people per square mile, compared to only 10 people per square mile for the three highest in the rural county sample. Although some counties with lower population densities are included in the state-wide seat belt survey sample, the counties selected for that survey include the most populated — thus most urban — counties in the state. Twenty-four of the 37 counties not surveyed in the NOPUS survey were surveyed in this project (Figure 2.2). Within the sample counties, sites selected for observation were based on local traffic knowledge because annual vehicle miles travelled, or traffic density, is not available for local roads. Observations were conducted in July 2015. The seat belt observations were performed by experienced seat belt survey observers. Prior to conducting county observations, observers were asked to become familiar with the “Rural Seat Belt Observation Training Guide” which outlined specific procedures recommended for conducting rural seat belt observations in North Dakota, including the data collection tool (Appendix A). (Author/publisher)
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