Year of Publication



Martin School of Public Policy and Administration

Executive Summary


The traffic safety community is interested in reducing the number of lives lost and injuries due to automobile accidents. This can be done in two ways, through advancing automobile safety technology and by changing automobile driver behavior (Desai and You 1992). Seat belt laws are thought to be the behavioral solution because they have been proven to increase seat belt usage among automobile occupants. However, studies on the topic have varying answers when it comes to the degree to which these laws increase seat belt usage and factors which influence on seat belt uses.

Research Questions:

This study uses meta-analytic techniques to explore whether certain variables influence seat belt usage rates. The main research questions posed in this study are:

  1. What common independent variables are included in the studies of the impact of seat belt laws?
  2. Does the inclusion of certain variables affect the findings of the studies?
  3. In what direction do these variables influence the results of the study?

The research hypothesis is that the inclusion of independent variables will have an effect on the influence of seat belt laws on seat belt use.

Research Design:

This study used a meta-analytic technique to pool data from five studies. A multiple regression was used to observe relationships between the dependent variable (percentage point increase in seat belt use) and independent variables such as race, gender, unit of interest, number of years included to the study, number of observations, year of publication and data source. A bivariate regression was used to further explore the relationships between the dependent and independent variables. Additionally, a qualitative review was conducted which included the seat belt law studies selected for inclusion in the meta-analysis.


The multiple regression procedure using was not successful run due to the limited number of observations in this study. However, a bivariate regression analysis found correlations between percentage point increases in seat belt use and the primary seat belt law, secondary seat belt law, number of observation, unit of interest, and year published variables in a bivariate regression.


This study did provide some insight into variables that influence seat belt rates however not many conclusions can be drawn from this study. Further research must be done to gain a better grasp of the factors that influence seat belt usage rates. Future meta-analytic studies on the seat belt laws and seat belt usage rates should include more studies and have broader set of criteria for the inclusion of studies and compare and contrast studies which examine studies that examine only primary or secondary laws.