I-15 / I-86 Corridor Plan Corridor Plan prepared for: Idaho Transportation Department | March 2011 prepared by: I-15/I-86 Corridor Plan, Project No. A009(884), Key No. 09884 TABLE OF CONTENTS Page 1.0 INTRODUCTION .......................................................................................................................................... 1-1 2.0 EXISTING TRANSPORTATION CONDITIONS ........................................................................................... 2-1 2.1 Overview of Existing Roadway ....................................................................................................... 2-1 2.2 Existing Traffic Volumes ................................................................................................................. 2-2 2.3 Existing Traffic Control ................................................................................................................... 2-3 2.4 Current and Planned Roadway Improvements .............................................................................. 2-3 2.5 Existing Intersection Operations ..................................................................................................... 2-3 2.6 Turn Lane Warrants ..................................................................................................................... 2-16 2.7 Safety .......................................................................................................................................... 2-21 2.7.1 Existing Crash History .................................................................................................... 2-21 2.7.2 High Crash Locations ..................................................................................................... 2-23 2.8 Functional Classification and Access Control .............................................................................. 2-23 2.9 Freight Facilities ........................................................................................................................... 2-25 2.10 Transit Services ........................................................................................................................... 2-25 2.10.1 Transit Planning ............................................................................................................. 2-25 2.10.2 Existing Transit Providers .............................................................................................. 2-25 2.11 Other Transportation Services ..................................................................................................... 2-26 2.11.1 Commercial Air Service ................................................................................................. 2-26 2.11.2 Rail Service .................................................................................................................... 2-27 2.11.3 Rest Areas ..................................................................................................................... 2-27 2.12 Existing Interstate Corridor Roadway Geometrics........................................................................ 2-27 2.12.1 Types of Deficiencies ..................................................................................................... 2-27 2.12.2 Summary of Horizontal Geometric Deficiencies ............................................................. 2-29 2.12.3 Recent Mainline Maintenance ........................................................................................ 2-29 2.13 Existing Structures ....................................................................................................................... 2-30 2.13.1 I-15 Structures ............................................................................................................... 2-30 2.13.2 I-86 Structures ............................................................................................................... 2-31 3.0 LAND USE AND DEMOGRAPHICS ............................................................................................................ 3-1 3.1 Existing Land Use .......................................................................................................................... 3-1 3.1.1 I-86 Corridor: West American Falls Interchange to the I-15 Interchange (MP 63) .......... 3-1 3.1.2 I-15 Corridor: McCammon Interchange (MP 47) to South Idaho Falls Interchange (MP 113) .......................................................................................................................... 3-1 3.2 Comprehensive Plans Stakeholder Interviews and Other Planning Documents ............................ 3-3 3.2.1 Stakeholder Interviews ..................................................................................................... 3-3 i I-15/I-86 Corridor Plan, Project No. A009(884), Key No. 09884 3.2.2 Summary of Comprehensive Plans and Stakeholder Comments .................................... 3-3 3.3 Current and Future Demographics ................................................................................................. 3-6 3.3.1 Countywide Assessments ................................................................................................ 3-6 3.4 Corridor and Traffic Zone Assessment ........................................................................................... 3-8 3.4.1 2008 Population, Housing Units, and Employment .......................................................... 3-8 3.4.2 2030 Corridor Forecast .................................................................................................... 3-9 4.0 FUTURE TRANSPORTATION CONDITIONS ............................................................................................. 4-1 4.1 Methodology to Develop Year 2030 Traffic Projections ................................................................. 4-1 4.2 Future Baseline Transportation Conditions .................................................................................... 4-2 4.2.1 Overview of Future Roadway ........................................................................................... 4-2 4.2.2 Future Traffic Volumes ..................................................................................................... 4-3 4.3 Year 2030 Baseline Intersection Operations .................................................................................. 4-5 4.3.1 Future Level-of-Service .................................................................................................... 4-5 4.4 Operational Deficiencies .............................................................................................................. 4-17 4.5 Safety ........................................................................................................................................... 4-17 5.0 ENVIRONMENTAL SCAN ........................................................................................................................... 5-1 5.1 Climate ........................................................................................................................................... 5-1 5.2 Topography and Geology ............................................................................................................... 5-1 5.3 Soils and Farmlands ...................................................................................................................... 5-2 5.4 Water Resources ........................................................................................................................... 5-3 5.4.1 Floodplains ...................................................................................................................... 5-3 5.4.2 Surface Waters ................................................................................................................ 5-3 5.4.3 Groundwater .................................................................................................................... 5-9 5.4.4 Wetlands .......................................................................................................................... 5-9 5.5 Wildlife Habitat ............................................................................................................................. 5-18 5.6 Threatened and Endangered Species .......................................................................................... 5-18 5.6.1 Utah Valvata Snail ......................................................................................................... 5-19 5.6.2 Canada Lynx .................................................................................................................. 5-19 5.6.3 Yellow-billed Cuckoo ...................................................................................................... 5-19 5.7 Historic and Cultural Resources ................................................................................................... 5-19 5.8 Potential Hazardous Sites ............................................................................................................ 5-27 5.9 Air Quality ..................................................................................................................................... 5-29 6.0 PURPOSE AND NEED, GOALS AND OBJECTIVES 6.1 Transportation Needs ..................................................................................................................... 6-1 6.2 Purpose of Corridor Plan 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