Safety is key component of the North Carolina Strategic Transportation Investments (STI) scoring process. For many projects, the potential for safety improvements in the STI process is evaluated using Safety Benefit Factors (SBFs). SBFs can be used to estimate the safety improvements that can be expected with the implementation of a project. Yet, the NCDOT currently either lacks SBFs or has limited evidence to support the SBFs used for several types of projects due to a lack of current research as well as the complex nature of the projects. Consequently, to help NCDOT ensure the STI safety evaluation process is as defensible and data-driven as possible, this research study focuses on developing evidence-based SBFs for these project types and providing enhanced methods for applying these SBFs.
Specifically, this research will develop SBFs and enhance safety analysis methods for various types of new location projects (e.g. bypass, loops, road extensions, etc.) and widening projects (e.g. urban widening, widening to multi-lane divided facility, widening to a superstreet facility, etc.) in the STIprocess. This study will help NCDOT identify factors that more accurately reflect the safety benefits of various types of new location projects and widening projects, filling a gap that currently exists in the safety component of the STI process and enhancing the current state of knowledge on how new location and widening projects impact safety. Taking into account the limited amount of data available at the time projects are scored, the research team will develop SBFs and guidance that can be easily integrated into the current STI process. Consistent with NCDOT’s method of selecting SBFs, a key point of the team’s approach will be incorporating existing crash modification factors (CMF) knowledge from research studies. The research team will accomplish the goal of this project through 1) a kickoff meeting, 2) a literature review, 3) the establishment of SBF recommendations for North Carolina, 4) an evaluation of SBF model outcome scenarios, 5) the development of a framework for applying SBFs for different project types, and 6) production of a final report.