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1-5:Aurora Donald Interchange(Exit 278) Interchange Area Management Plan for Marion County Approval ODOT KN19062 Oregon Department of Transportation—Region 2 EXECUTIVE SUMMARY Background An Interchange Area Management Plan (TAMP) is an Oregon Department of Transportation (ODOT) long-term (20+years)transportation facility plan.' Facility plans are one of the three levels of plans implemented by ODOT. The Oregon Transportation Plan is the highest level, providing overall goal and policy guidance for planning and development of the state's transportation system. "Mode and topic" plans, such as the Oregon Highway Plan (OHP), are the next level and provide more specific goals and policies for the entire state highway system. Facility plans apply these system policies to a specific area or segment of highway such as an interchange. This TAMP for the 1-5: Aurora Donald Interchange (Exit 278) Project (Project) establishes agreement between ODOT, local government, and stakeholders on the transportation solutions, policies, and actions needed to improve the interchange.This TAMP was prepared in accordance with the ODOT 2013 TAMP Guidelines and reflects close coordination between ODOT, Marion County, interchange area stakeholders, and the broader community. This TAMP differs from a traditional TAMP since it was developed in tandem with, not in advance of,the interchange engineering design process. The TAMP planning process served as a Project design development tool to analyze interchange area Project needs, environmental considerations, and alternative interchange design solutions along with its more traditional planning and policy focus within the TAMP study area (see Figure 1-1).This expanded scope was needed to address implementation funding made available in 2017 by the Oregon Legislature through the 2017 Keep Oregon Moving Act for the construction of a first phase (Phase 1) of the Project. This TAMP recommends both operational and physical improvements, including access management for the interchange and the county road system, along with changes to Marion County transportation policy supporting plan recommendations. Problem The Aurora Donald Interchange was built with Interstate 5 (1-5) in the 1960s. Since its construction, design criteria for the interstate, bridges, and on-and off-ramps have changed with higher typical travel speeds and increased traffic volumes. In addition to its age and outdated design,the interchange's functional performance is substandard. Traffic volumes on the off-ramp from southbound I-5 to Ehlen Road and on Bents Road (approaching Ehlen Road) exceed intersection capacity. Additionally,the proximity of the intersections to each other(about 50 feet apart) is unsafe. Both 1-5 on-ramps have an uphill grade, causing slow-speed merging of trucks onto 1-5 and vehicles closely following large trucks. The grade of Ehlen Road below 1-5,with significant horizontal and vertical curves, restricts sight distance at both ramp terminals, creating unsafe conditions. Land use in the area, including two truck stops, draws substantial large-truck traffic, resulting in frequent slow acceleration and turning movements that impact county roads and 1-5.These congestion and safety concerns negatively impact the mobility of freight, agricultural goods, and passenger vehicles in the region. Per Oregon Administrative Rule(OAR)731-015. July 2020 1274-3012-031 ES-1