University of Washington

19 2014-2015 Annual Report • Project: Aerodynamic Effects on Two-Lane Highway Safety • PI: Tao Xing (UI), xing@uidaho.edu Rural roads are more dangerous than urban roads. Only 19 percent of Americans live in rural areas, but 55 percent of all road fatalities occurred in those rural locations. Many of these rural vehicle fatalities were on two-lane roads, which is caused by several factors: most rural highways are un-separated two-lane roadways, drivers drive at faster speed in rural areas, wind speeds are much higher, and the wind direction relative to the vehicles also change very quickly due to the curved roadways. The stability and safety of vehicles during crossing and overtaking maneuver under cross-wind conditions are of great concern. This subject has not been well studied and understood at date. The goal of this project is to use advanced computational fluid dynamics (CFD) models and wind tunnel experimental measurements to study the effects of aerodynamics on two-lane rural highway safety in the United States. The project focuses on the changes of forces and moments in three dimensions during the crossing and overtaking process between cars and trucks under various environmental wind conditions, especially cross-wind. Additionally, this research will allow us to better understand the stability and safety of the vehicles. The data produced in this project will help modify/improve existing highway policies and/or designs of automobiles to improve the stability and safety. • Project: Improved Safety and Efficiency of Protected/Permitted Right Turns for Bicycles in the Pacific Northwest • PI: David Hurwitz (OSU), david.hurwitz@oregonstate.edu The design of phasing schemes at signalized intersections are complex multifaceted transportation engineering problems. Right-turn operations place a significant challenge to engineers attempting to develop optimal phasing solutions for safety and efficiency. There is a surprising absence of specific guidance at the national and state level on how phasing alternatives should be selected, and how they compare in terms of operational and safety performance. The challenge of designing the phasing schemes for protected/permitted right turns has been widely identified by local traffic signal experts, presenting an opportunity for a research-based solution. While traffic engineers have a good understanding of driver comprehension and response to the circular green ball or a solid green arrow for right turning movements, significant questions remain regarding the flashing yellow arrow (FYA) for right turn movements, specifically what the implications will be on pedestrian and bicycle traffic. The goal of the research is to develop an understanding of the safety and operational implications of using the FYA to indicate a permitted right turn, and to provide general guidance as to when Protected/Permitted Right Turn (PPRT) phasing should be used to maximize the safety of non-motorized road users and the overall efficiency of signalized intersections in the Pacific Northwest. This goal is consistent with the PacTrans theme of Safe Travel on Mixed- Use Roads as the primary focus is to improve the safety of pedestrians and bicyclists in close proximity turning vehicles at signalized intersections.

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