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1 Summary Driver distraction has primarily been considered in the context of driver behaviors (e.g., texting, eating, personal grooming) or situations within the vehicle (e.g., interacting with passengers, adjusting vehicle controls). However, a significant number of distractions occur outside the vehicle, and many of these may be related to the presence of infrastructure features. BTSCRP Project BTS-09, Influence of Infrastructure Design on Distracted Driving, was conducted to develop methodologies (referred to as Safety Frameworks) that can be used by agencies to assess the impact of infrastructure elements on driver distraction. For the purposes of this project, infrastructure was defined as any fixed object that forms part of the roadway cross section, including the roadway itself, the shoulder, the median, and any right- of-way owned or operated by the corresponding roadway agency. Additionally, other fixed objects may be considered infrastructure if they are located adjacent to the roadway and their primary function is related to the traveling public (e.g., billboards) or a transportation agency is reasonably likely to be able to implement a policy addressing their use or placement (e.g., monuments or wind turbines). The first phase of the study included a review of existing information about the relationships between distraction and specific infrastructure elements. The vast majority of the published research on infrastructure-related distraction (IRD) has centered on the effects of billboards. A few studies have explored the distraction potential of traffic signs, urban clutter, wind turbines, railroad crossings, and geometric features, but the results have been limited. Also in this phase, sources of existing public and private data were identified that could be used in the development of the Safety Frameworks during the second phase of the study. The identified data sets were grouped into four categories: naturalistic driving study, crash, infrastructure, and driving simulator data sets. Each data set was evaluated in terms of the feasibility of its use in assessing IRD. The second phase of the study focused on developing a set of five conceptual Safety Frameworks to demonstrate the use of the identified data sets in evaluating the association between distracted driving and roadway or roadside infrastructure. Safety Frameworks were developed for each type of data that had shown promise for evaluating IRD: crash narratives, crash data, naturalistic driving study data, and driving simulator data. One framework each was developed for crash narrative data, crash data, and driving simulator data, and two frameworks were developed for naturalistic driving study data. Each Safety Framework provides an overview of the type of analysis conducted using the data source; identifies the research questions that could be considered given the type of data used; describes the specific data sets utilized and the details of the analysis conducted, including variables, statistical methods, and results; and discusses the efficacy of the approach. The Safety Frameworks are intended as templates to guide agencies and other stakeholders in using a particular data source to assess the distraction potential of a specific infrastructure element.
