Project Details

Abstract

Alternative intersection and interchange designs, such as the Diverging Diamond Interchange (DDI) and the Continuous Flow Intersection (CFI), have garnered significant attention among transportation agencies, researchers and practitioners over the past 15 years, due to their ability to improve operations and safety of transportation systems. The Utah Department of Transportation (UDOT) is recognized as a national leader in the design and implementation of innovative intersections and interchanges. Currently there is not a lot of information on field-based performance measures of these designs. As it has been 16 years since the first CFI was implemented, followed by many more CFIs and DDIs, UDOT's databases contain a lot of useful data regarding operations and safety of these designs. The accelerated deployment of DDIs and CFIs necessitates the needs for more in-depth assessment of their benefits and impacts. The objective of this study is to perform safety and operational assessment of CFIs and DDIs in Utah. It will develop Utah-specific Safety Performance Functions (SPFs) and Crash Modification Factors (CMFs) for these designs. The study will also assess the operational performance of CFIs and DDIs, and explore ways in which operations can be improved (geometry, control, signalization).

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