Adaptation Analysis for Cost-Effective Transportation with GHG Reduction at an AWSC Intersection

Abstract: Various traffic control alternatives exist at roadway crossings, including roundabouts, signalized and unsignalized (or sign-controlled) intersections, and elevated interchanges. Compared to roundabouts, both traffic light-controlled intersections and elevated interchanges can handle higher traffic volumes but come with significantly higher capital costs. On the other hand, sign-controlled unsignalized intersections, such as all-way and three-way stop-controlled (AWSC and TWSC) intersections, offer a low-cost solution for uncongested crossings, but they can result in significant queuing delays during periods of high traffic volume. For unsignalized intersections near schools, traffic congestion during specific morning and afternoon hours, with low traffic at other times, poses unique challenges in traffic management. The design and deployment of the most effective solution must balance the need for efficient traffic operations during peak hours with cost-effectiveness during off-peak periods, all while considering the importance of reducing greenhouse gas (GHG) emissions.

In this student-led research project, conducted through an expanded high-school Advanced Placement (AP) Research class, we focus on a road crossing near Indian Hill High School in the Village of Indian Hill, Ohio, where traffic congestion commonly occurs during school arrival and departure times. This two-lane crossing connects north-south Drake Road and east-west Shawnee Run Road, and is adjacent to three schools. The site also includes a community fire station, the Village’s waterworks administrative building to the west, and Stephen Field and Indian Hill Memory Park to the east. The crossing at Drake Road and Shawnee Run Road is an AWSC intersection, where traffic congestion occurs between 7-8 a.m. and 2:45-3:45 p.m., as school buses, students, and residents travel to and from school and work.

Based on a warrant analysis, we recommended implementing time-of-day signal control during peak hours, with a flashing red light replacing stop signs during off-peak times. Other potential improvements include constructing a roundabout or widening the road, while also considering the operational needs of the fire station and preserving communal green space. Analytical tools, including Highway Capacity Software, the U.S. Environmental Protection Agency’s Motor Vehicle Emission (MOVES) software, and the Ohio Department of Transportation’s Tool for Estimated Signal Retiming Benefits, will be used to conduct a holistic evaluation of traffic mobility, GHG emissions, and associated costs for three alternatives: 1) the existing AWSC control, 2) the proposed time-of-day signal control, and 3) roundabout control. A look-up matrix will compare the benefits and limitations of these alternatives, providing the community with valuable insights for developing smart traffic management adaptations.