Nighttime seatbelt usage data collection: When and how long?

Abstract

Higher proportion of non-seatbelt usage rates in crashes occurring during nighttime shows that daytime seatbelt usage alone may not indicate the overall usage patterns. These findings have prompted various agencies to estimate seatbelt usage rates during nighttime. These agencies developed their own methodology for data collection and data analyses. In spite of all these recent developments, collecting representative sample at nighttime remains an issue which requires a lot of effort. This paper is an attempt to develop a methodology to collect nighttime seatbelt usage data more efficiently and accurately based on a mathematical sampling theory. Based on this methodology, two sets of data collection per site are recommended. Duration of data collection varies depending on vehicle miles traveled at the site of interest. The authors hope that this methodology could be used in other transportation related data collection efforts, where identifying critical time and time duration for collecting representative data samples are important.