Safety
is a key component of the project scoring process conducted by NCDOT as part of
the 2013 Strategic Transportation Investments (STI) law. For most improvement
types in the STI process, Safety Benefit Factors (SBFs) are used to quantify
the benefits expected from a reduction in crashes stemming from a given
project.
This study fills a gap that currently exists in the safety component
of the STI process and enhancing the current state of knowledge on how new
location projects (e.g. bypass, road extensions, etc.) and widening projects
(e.g. rural and urban areas, widening to multi-lane divided facility, etc.) can
impact safety. Taking into account the limited amount of data available at the
time projects are scored, the research team developed SBFs and guidance that
can be easily integrated into the current scoring process. Consistent with
NCDOT’s method of selecting SBFs, the research team focused on incorporating
practices from the Highway Safety Manual (HSM) as well as existing crash
modification factors (CMF) knowledge from research studies.
In total, this
study resulted in the generation of 10 new SBFs for NCDOT and the confirmation
of 2 SBFs already utilized by NCDOT, as outlined in the following table.
Additionally, approaches for developing SBFs using North Carolina project and
crash data were also developed through this research.
These findings and
approaches can be used by NCDOT into the future to develop more reliable
estimations of safety benefits for proposed projects, and ultimately improve the
quality of North Carolina transportation projects developed in the future
