ROUTE REPAIR: DESIGN CHANGES TO IMPROVE SAFETY AT MOUNTAIN AVENUE AND HELEN STREET

Abstract

The intersection of Mountain Avenue and Helen Street in the city of Tucson, Arizona, lies at the end of a high use pedestrian and cyclist corridor. The intersection is located near the University of Arizona and is vital in facilitating walking and cycling connections to the university as well as the greater surrounding areas, including downtown Tucson. The intersection is currently unsafe and inefficient as a result of both design and location. This Thesis attempts to analyze and provide recommendations for potential design changes that would increase both vehicle levels of service and safety for all road users. A case study of successful cities and nationally recommended best practice design strategies was conducted to determine what features and infrastructure could be implemented to improve the intersection. It was found that safety infrastructure at intersections and connectivity between safe intersections were among the best practices for improved bicyclist and pedestrian safety. An application of these designs to the study intersection was explored with several alternatives offered. The application of left turn and straight through restrictions for automobiles proved the most promising design change. A significant increase in the level of service of the intersection was observed along with a 66% decrease in the number of conflict points at the intersection, a proxy for intersection safety. In conclusion, it is recommended that turning restrictions be implemented at this intersection to improve walking and cycling safety and connectivity in the greater university region of the city ot Tucson.