TRAFFIC CALMING PROTOCOL MANUAL Prepared for: Municipality of Anchorage Traffic Department 4700 S. Bragaw Street Anchorage, Alaska 99507 Prepared by: DOWL Engineers 4040 B Street Anchorage, Alaska 99503 W. O. D56869 March 2001 Traffic Calming Protocol Manual March 2001 TABLE OF CONTENTS Page 1.0 INTRODUCTION AND OBJECTIVES............................................................................ 1 2.0 APPLICABILITY AND PROCEDURES.......................................................................... 3 2.1 Steps in the Process....................................................................................................... 4 2.1.1 Project Initiation.................................................................................................... 4 2.1.2 Project Selection.................................................................................................... 4 2.1.2.1 Screening........................................................................................................... 4 2.1.2.2 Priority Rating................................................................................................... 5 2.1.3 Plan Development ................................................................................................. 7 2.1.3.1 Impact Area ....................................................................................................... 7 2.1.3.2 Neighborhood Traffic Committee..................................................................... 8 2.1.3.3 Traffic Calming Framework Plan...................................................................... 8 2.1.3.4 Public Workshop............................................................................................... 9 2.1.4 Trial ....................................................................................................................... 9 2.1.5 Implementation...................................................................................................... 9 3.0 REGULATORY AND RESOURCE AGENCY CONCERNS ....................................... 12 3.1 General ........................................................................................................................ 12 3.2 Specific Agency Concerns .......................................................................................... 12 3.2.1 Municipality of Anchorage Planning .................................................................. 12 3.2.2 Emergency Services ............................................................................................ 12 3.2.3 Street Maintenance.............................................................................................. 13 3.2.4 Solid Waste Services........................................................................................... 13 3.2.5 Transit Service..................................................................................................... 13 3.2.6 Anchorage School District .................................................................................. 14 3.2.7 Utility Companies ............................................................................................... 14 4.0 TRAFFIC CALMING TOOLBOX.................................................................................. 14 4.1 Toolbox of Traffic Calming Measures........................................................................ 15 4.1.1 Volume Control Measures .................................................................................. 15 4.1.2 Vertical Speed Control Measures........................................................................ 18 4.1.3 Horizontal Speed Control Measures ................................................................... 20 4.1.4 Narrowings .......................................................................................................... 22 4.1.5 Combined Measures............................................................................................ 24 4.2 Effectiveness and Impacts of Traffic Calming Measures............................................ 24 4.2.1 Full and Half Closures......................................................................................... 27 4.2.2 Diverters.............................................................................................................. 28 4.2.3 Speed Humps....................................................................................................... 29 4.2.4 Traffic Circles/Roundabouts ............................................................................... 33 4.2.5 Chicanes and Lateral Shifts................................................................................. 34 4.2.6 Neckdowns and Chokers..................................................................................... 35 Page i Traffic Calming Protocol Manual March 2001 4.3 Non-Engineering Measures......................................................................................... 35 4.3.1 Increased Enforcement ........................................................................................ 36 4.3.2 Variable Speed Display....................................................................................... 36 4.3.3 Signage and Striping ........................................................................................... 37 4.4 Application Guidelines................................................................................................ 38 4.4.1 Relationship to Roadway Functional Classification ........................................... 38 4.4.2 Relationship to Traffic Volumes and Speeds...................................................... 38 4.4.3 Summary of Guidelines....................................................................................... 39 5.0 GEOMETRIC DESIGN................................................................................................... 41 5.1 General Guidance........................................................................................................ 41 5.2 Volume Control Measures .......................................................................................... 42 5.2.1 Full Closures ....................................................................................................... 42 5.2.2 Half Closures....................................................................................................... 42 5.2.3 Other Volume Control Measures ........................................................................ 45 5.3 Vertical Speed Control Measures................................................................................ 48 5.3.1 Speed Humps....................................................................................................... 48 5.3.2 Speed Tables ....................................................................................................... 50 5.3.3 Raised Crosswalks and Raised Intersections....................................................... 52 5.3.4 Accommodation of Bicyclists ............................................................................. 55 5.3.5 Design Modifications for Hilly Terrain............................................................... 55 5.4 Horizontal Speed Control Measures ........................................................................... 57 5.4.1 Traffic Circles ..................................................................................................... 57 5.4.2 Roundabouts........................................................................................................ 61 5.4.3 Chicanes .............................................................................................................. 63 5.4.4 Lateral Shifts ....................................................................................................... 65 5.4.5 Accommodation of Bicyclists ............................................................................. 65 5.5 Narrowings .................................................................................................................. 65 5.5.1 Neckdowns.......................................................................................................... 65 5.5.2 Chokers................................................................................................................ 67 5.5.3 Center Island Narrowings.................................................................................... 69 5.6 Speed Estimates........................................................................................................... 71 5.6.1 Speed Versus Vertical Curvature ........................................................................ 71 5.6.1.1 Speed Humps................................................................................................... 71 5.6.1.2 Speed Tables ................................................................................................... 72 5.6.2 Speed Versus Horizontal Curvature.................................................................... 73 5.6.3 Speed Versus Spacing of Slow Points................................................................. 76 5.7 Signage and Striping ................................................................................................... 78 5.7.1 General Guidance from Manual of Uniform Traffic Control Devices ................ 78 5.7.2 Standard Signs..................................................................................................... 79 5.7.2.1 Standard Manual of Uniform Traffic Control