Research Reports
Report Details
Final Report Abstract
The purpose of North Dakota’s seat belt use study is to provide statistically reliable data from which generalizations, comparative analyses and recommendations can be developed. The National Occupant Protection Use Survey (NOPUS) provides the North Dakota Department of Transportation (NDDOT) with a system that monitors the seat belt usage (SBU) rates within the state. The National Highway Traffic Safety Administration (NHTSA) funds NOPUS through the NDDOT’s Traffic Safety Office.
The sampling methodology for this study was originally developed in 2001 with guidance from NHTSA and it has remained stable since then, with relatively no change in the counties and sites that make up the sample. The only major change was to update the site and county vehicle miles travelled (VMT) to the latest NDDOT estimates for the 2009 survey. This change affected the determination of sampling probabilities for some sites. All reports from 2001 through 2008 used the same VMT estimates while the 2009 through 2011 reports used the 2009 updated estimates.
The 2011 survey was based on a random probability sample of 16 North Dakota counties and 319 observation sites developed for and approved by NHTSA in 2001. Trained observers used the week of June 6-10 to visit each site in their assigned county and collect the seat belt use data as prescribed in the handbook they received at training. Front seat drivers and outboard passengers in automobiles, vans, sport utility vehicles (SUVs), and pickup trucks were observed for seat belt use. Observation data forms from each site were submitted for entry and analysis.