A comprehensive assessment of possible links between digital advertising billboards and traffic safety

Advertising billboards are a common roadside object and a very efficient medium of outside advertising. For years, static billboards have been adopted by the billboard advertising companies. Most recently, a sizeable portion of the regular (static) billboards have been digitized to convey more information to the drivers, thus raising questions about their potential impact on traffic safety. Frequently changing images on digital advertising billboards may compel more glances, and sequential messages may hold drivers' gazes longer until the entire message is read.;Earlier studies sponsored by billboard advertising companies did not report statistically significant correlations between the crash occurrences and the presence of digital billboards. Some other studies tried to show potential relationship between diminished attention caused by digital billboards to crashes but suffered from methodological problems and did not succeed due to lack of sufficiently reliable manner. So, there is an ongoing debate surrounding this issue and a need for an objective and reliable evaluation to determine if the presence of digital billboards really distracts driver's attention or not and, if distraction occurs then to what extent.;To bridge these gaps, this thesis studied the correlation between the presence of digital billboards and traffic safety through a. literature review, b. driver questionnaire survey, and c. crash data analysis. The literature review involved a comprehensive review and synthesis of findings from existing studies on digital advertising billboards, driver distraction and traffic safety. The survey of road users focused on the development of a questionnaire survey that was used to survey Alabama drivers and document road user's perceptions and attitudes related to roadside advertising billboards. The crash analysis involved an analysis of historical crashes along selected interstate routes in Alabama to determine if the presence of digital billboards has an impact on crash occurrence. The goal was to compare the frequency of crashes within the billboard area of influence to crash frequencies at adjacent comparison sites. The crash rate by type and severity has also been determined at u/s (or, study site or influence zone) and d/s (or, control site or non-influence zone) of digital billboard locations.;The findings of this thesis are expected to assist policy makers to better understand the effect of digital billboards from the safety viewpoint. If required, amendments for digital billboard size and location guidelines may be introduced for improving the overall safety of road users.