The purpose of this report is to document the survey design used for the initial data collection of the National Survey of the Use of Booster seats (NSUBS). The initial data collection occurred in 2006. Although this report is being published after the second data collections (which occurred in 2007) and as NHTSA is preparing for the third data collection (in 2008), this report serves as important documentation as the design used for subsequent NSUBS data collections were based on the design documented in this report, incorporating relatively minor changes in methodology. NHTSA expects to publish annual methodology reports that document subsequent changes in methodology.