Using personal digital assistants (PDAs) for the collection of safety belt use data in the field

From 1975 through 2003, because of the use of safety belts, an estimated 180,000 deaths from traffic crashes have been prevented. In order to assess the gains that have been made in safety belt use across the U.S., in individual states, and in communities, belt use surveys are conducted at regular intervals to determine use rates. The most valid method for surveying safety belt use is through direct observation. Direct observation surveys are conducted along roadways by trained researchers looking into passing vehicles and recording safety belt use. This method of data collection has been effective in the past through the use of paper-and-pencil data recording, yet it could be improved through the use of electronic and communication technology. Reported here is a study designed to compare electronic data collection, using personal digital assistants (PDAs), with collection using the traditional paper-and-pencil method during the annual statewide survey of safety belt use in Michigan that we have been conducting since 1984. The goals of the study were to develop a PDA database program for data entry in the field, to directly compare the PDA data collection process with the paper-and-pencil method on both accuracy and speed, and to assess mechanical and environmental factors, such as battery life, screen visibility, and reaction to adverse weather, that may act as limitations to the PDA method, in comparison with the paper-and-pencil method. In a direct comparison of methods, two observers collected data at the same roadway intersections, one using paper and a pencil and one using a PDA equipped with our custom software. The study showed that the PDA method was as fast and as accurate as the paper-and-pencil method. There were no adverse effects on the PDA caused by environmental conditions. The PDA was superior to the paper-and-pencil method in rainy weather and for data collector supervision. In addition, the use of the PDA obviated the need for entry of paper-recorded data into an electronic format. We conclude that the use of PDAs for safety belt field data collection is superior to the paper-and-pencil method. A Web address is given where the custom PDA safety belt data collection software can be obtained free of charge.