Table of Contents. PREFACE... vii LIST OF FIGURES... xvii LIST OF TABLES... x xii

Transcription

1 Table of Contents PREFACE... vii LIST OF FIGURES... xvii LIST OF TABLES... x xii CHAPTER 1: AN INTRODUCTION TO ROADSIDE SAFETY 1.0 HISTORY OF ROADSIDE SAFETY THE BENEFITS OF ROADSIDE SAFETY THE FORGIVING ROADSIDE CONCEPT THE CONTENT AND FORMAT CRASH TESTING ROADSIDE SAFETY FEATURES AND APPURTENANCES THE APPLICATION OF THIS GUIDE CHAPTER 2: ROADSIDE SAFETY AND ECONOMICS 2.0 OVERVIEW BENEFIT/COST ANALYSIS Encroachments Roadside Geometry Crash Costs BENEFIT/COST ANALYSIS PROGRAMS CHAPTER 3: ROADSIDE TOPOGRAPHY AND DRAINAGE FEATURES 3.0 OVERVIEW THE CLEAR ROADSIDE CONCEPT ROADSIDE GEOMETRY Foreslopes Backslopes Transverse Slopes Drainage Channels APPLICATION OF THE CLEAR-ZONE CONCEPT Recoverable Foreslopes Non-Recoverable Foreslopes Critical Foreslopes Examples of Clear-Zone Application on Variable Slopes Clear-Zone Applications for Drainage Channels and Backslopes DRAINAGE FEATURES ix

2 3.4.1 Curbs Cross-Drainage Structures Traversable Designs Extension of Structure Shielding Parallel Drainage Features Eliminate the Structure Traversable Designs Relocate the Structure Shielding Drop Inlets CHAPTER 4: SIGN, SIGNAL, AND LUMINAIRE SUPPORTS, UTILITY POLES, TREES, AND SIMILAR ROADSIDE FEATURES 4.0 OVERVIEW ACCEPTANCE CRITERIA FOR BREAKAWAY SUPPORTS DESIGN AND LOCATION CRITERIA FOR BREAKAWAY AND NON-BREAKAWAY SUPPORTS SIGN SUPPORTS Overhead Signs Large Roadside Signs Small Roadside Signs MULTIPLE POST SUPPORTS FOR SIGNS BREAKAWAY LUMINAIRE SUPPORTS SUPPORTS FOR TRAFFIC SIGNALS AND MISCELLANEOUS TRAFFIC SERVICE DEVICES Traffic Signals Motorist-Aid Callboxes Railroad Crossing Warning Devices Fire Hydrants Mailbox Supports UTILITY POLES TREES CHAPTER 5: ROADSIDE BARRIERS 5.0 OVERVIEW PERFORMANCE REQUIREMENTS Current Crash Test Criteria Barrier Classifications WARRANTS Embankments Roadside Obstacles Bystanders, Pedestrians, and Bicyclists Motorcycles and Barrier Design PERFORMANCE LEVEL SELECTION FACTORS x

3 5.4 STRUCTURAL AND SAFETY CHARACTERISTICS OF ROADSIDE BARRIERS Standard Sections of Roadside Barriers Three-Strand Cable W-Beam (Weak Post) Ironwood Aesthetic Guardrail Box Beam (Weak Post) Blocked-Out W-Beam (Strong Post) Blocked-Out Thrie-Beams Blocked-Out Thrie-Beam (Wood Strong Post) Blocked-Out Thrie-Beam (Steel Strong Post) Modified Thrie-Beam Merritt Parkway Aesthetic Guardrail Steel-Backed Timber Guardrail Concrete Barriers Stone Masonry Wall/Precast Masonry Wall Long-Span, Double-Nested Guardrail Systems Transition Designs SELECTION GUIDELINES Barrier Performance Capability Barrier Deflection Characteristics Site Conditions Compatibility Life-Cycle Costs Maintenance Routine Maintenance Crash Maintenance Material and Storage Requirements Simplicity of Barrier Design Aesthetic and Environmental Considerations Field Experience PLACEMENT RECOMMENDATIONS Lateral Offset Terrain Effects Curbs Slopes Flare Rate Length of Need UPGRADING SYSTEMS Structural Inadequacies Design/Placement Inadequacies Establishing Priorities of Upgrading Needs CHAPTER 6: MEDIAN BARRIERS 6.0 OVERVIEW PERFORMANCE REQUIREMENTS GUIDELINES FOR MEDIAN BARRIER APPLICATION xi

4 6.3 PERFORMANCE LEVEL SELECTION PROCEDURES STRUCTURAL AND SAFETY CHARACTERISTICS OF MEDIAN BARRIERS Crashworthy Median Barrier Systems Weak-Post, W-Beam Three-Strand Cable High-Tension Cable Barrier Box-Beam Median Barrier Blocked-Out W-Beam (Strong Post) Blocked-Out Thrie-Beam (Strong Post) Modified Thrie-Beam Median Barrier Concrete Barrier Quickchange Moveable Barrier System End Treatments Transitions SELECTION GUIDELINES Barrier Performance Capability Barrier Deflection Characteristics Compatibility Costs Maintenance Aesthetic and Environmental Considerations Field Experience PLACEMENT RECOMMENDATIONS Terrain Effects Fixed Objects within the Median UPGRADING SYSTEMS CHAPTER 7: BRIDGE RAILINGS AND TRANSITIONS 7.0 OVERVIEW PERFORMANCE REQUIREMENTS WARRANTS TEST LEVEL SELECTION PROCEDURES CRASH-TESTED RAILINGS Test Level 1 Bridge Railings Test Level 2 Bridge Railings Test Level 3 Bridge Railings Test Level 4 Bridge Railings Solid Concrete Bridge Railings Massachusetts S3 Steel Bridge Railing Wyoming Two-Tube Bridge Railing BR27C Test Level 5 Bridge Railings Test Level 6 Bridge Railings SELECTION GUIDELINES Railing Performance xii

5 7.5.2 Compatibility Costs Field Experience Aesthetics PLACEMENT RECOMMENDATIONS UPGRADING OF BRIDGE RAILINGS Identification of Potentially Deficient Systems Upgrading Systems Concrete Retrofit (Safety Shape or Vertical) W-Beam/Thrie-Beam Retrofits Metal Post and Beam Retrofits TRANSITIONS CHAPTER 8: BARRIER END TREATMENTS AND CRASH CUSHIONS 8.0 OVERVIEW PERFORMANCE REQUIREMENTS END TREATMENTS Three-Strand Cable Terminal Wyoming Box Beam End Terminal (WYBET-350) Barrier Anchored in Backslope Eccentric Loader Terminal (ELT) Slotted Rail Terminal (SRT-350) REGENT Terminal Vermont Low-Speed, W-Beam Guardrail End Terminal Flared Energy-Absorbing Terminal (FLEAT) Beam-Eating Steel Terminal (BEST) Extruder Terminal (ET-2000) Sequential Kinking Terminal (SKT-350) QuadTrend Narrow Energy-Absorbing Terminal (NEAT) Sloped Concrete End Treatment CRASH CUSHIONS Concepts Kinetic Energy Principle Conservation of Momentum Principle Characteristics of Operational Attenuation Systems Advanced Dynamic Impact Extension Module (ADIEM II) Brakemaster Crash Cushion Attenuating Terminal (CAT) Bullnose Guardrail System ABSORB QuadGuard Family Trinity Attenuating Crash Cushion (TRACC) Reusable Energy-Absorbing Crash Terminal (REACT 350) Narrow Connecticut Impact Attenuation System (NCIAS) Sand-Filled Plastic Barrels xiii

6 Gravel-Bed Attenuator Dragnet Water Twister Vehicle Arresting System (VAS) SELECTION GUIDELINES Site Characteristics Structural and Safety Characteristics Costs Maintenance Characteristics PLACEMENT RECOMMENDATIONS DELINEATION CHAPTER 9: TRAFFIC BARRIERS, TRAFFIC CONTROL DEVICES, AND OTHER SAFETY FEATURES FOR WORK ZONES 9.0 OVERVIEW THE CLEAR-ZONE CONCEPT IN WORK ZONES Application of the Clear-Zone Concept in Work Zones TRAFFIC BARRIERS Temporary Longitudinal Barriers Portable Concrete Safety-Shape Barriers Flare Rates Offset Types of Portable Concrete Barrier (PCB) Systems NCHRP Report 350 Tested PCB Systems Tested and Operational Connections Securing PCBs to the Traveled Way Special Cases Other Concrete Barriers Other Barriers Water-Filled Plastic Shell with Steel Barriers Triton Barrier GUARDIAN Safety Barrier Timber Barrier Curb/Rail End Treatments Transitions PCB Steel Plate Transition Applications CRASH CUSHIONS Stationary Crash Cushions Sand-Filled Plastic Barrels QUADGUARD CZ SYSTEM TRACC REACT 350 CZ Connecticut Impact Attenuation System (CIAS) ABSORB Advanced Dynamic Impact Extension Modules (ADIEM II) DRAGNET xiv

7 9.3.2 Truck-Mounted Attenuators (TMAs) Test-Level Selection for Truck Mounted Attenuators Placement Buffer Distance Mass of a Shadow Vehicle Delineation TMAs Meeting NCHRP Report 350 Criteria RENCO Ren-Gard 815 TMA Connecticut TMA ALPHA 70K TMA ALPHA 100K TMA Mobile Protection System Vanderbilt TMA Safe-Stop TMA U-MAD 100K TMA Scorpion A 10,000 and Scorpion C 10,000 TMAs RENCO RAM 100K TMA TRAFFIC CONTROL DEVICES Channelizing Devices Performance Evaluation Criteria Cones and Tubular Markers Vertical Panels Drums Barricades Longitudinal Channelizing Barricades Signs and Supports Long/Intermediate-Term Work-Zone Sign Supports Wheeled Portable Sign Supports Short-Term Work-Zone Sign Supports Trailer-Mounted Devices Warning Lights OTHER WORK-ZONE FEATURES Glare Screens Pavement Edge Drop-Offs CHAPTER 10: ROADSIDE SAFETY IN URBAN OR RESTRICTED ENVIRONMENTS 10.0 OVERVIEW NEED FOR INDIVIDUAL STUDY OF SITES DESIGN SPEED ROADSIDE BARRIERS IN URBAN AND RESTRICTED AREAS Barrier Warrants Barriers to Protect Adjacent Land Use Guidelines for Pedestrian and Bicyclist Barriers Pedestrian Restraint Systems xv

8 10.4 MEDIAN BARRIERS IN URBAN AREAS BRIDGE RAILINGS Protective Screening at Overpasses IMPACT ATTENUATORS CURBS DRAINAGE LANDSCAPING WORK ZONES CHAPTER 11: ERECTING MAILBOXES ON STREETS AND HIGHWAYS 11.0 OVERVIEW MAILBOXES GENERAL PRINCIPLES AND GUIDELINES Regulations Mail Stop and Mailbox Location Mailbox Turnout Design Mailbox Support and Attachment Design MODEL MAILBOX REGULATION APPENDIX A A Cost-Effectiveness Selection Procedure... A-1 APPENDIX B Selected Roadside Barrier Design Details... B-1 APPENDIX C Selected Median Barrier Design Details... C-1 APPENDIX D Model Regulation for the Accommodation of Mailboxes and Newspaper Delivery Boxes on Public Highway Rights-of-Way... D-1 APPENDIX E Postal Operations and Manual Delivery Services... E-1 GLOSSARY... G-1 INDEX... I-1 xvi

9 List of Figures Figure Title 1.1 Traffic fatality rate per billion vehicle kilometers [miles] by year a Clear-zone distance curves (metric units) b Clear-zone distance curves [U.S. customary units] Example of a parallel foreslope design Preferred cross slope design Median transverse slope design Examples of alternate median drainage Preferred cross sections for channels with abrupt slope changes Preferred cross sections for channels with gradual slope changes Design criteria for safety treatment of pipes and culverts Safety treatment for cross-drainage culvert Inlet/outlet design example for parallel drainage Alternate location for a parallel drainage culvert Safety treatment for parallel drainage pipe Breakaway support stub height measurements Wind and impact loads on roadside signs Impact performance of a multiple-post sign support Multidirectional coupler Typical uni-directional slip base Slotted fuse plate design Perforated fuse plate design Uni-directional slip base for small signs Multidirectional slip base for small signs Oregon 3-bolt slip base Example of a cast aluminum transformer base Example of a luminaire slip base design Example of a frangible coupling design Prototype breakaway design for utility poles a Comparative risk warrants for embankments (metric units) b Comparative risk warrants for embankments [U.S. customary units] a Example design chart for embankment warrants based on fill height, slope, and traffic volume (metric units) b Example design chart for embankment warrants based on fill height, slope, and traffic volume [U.S. customary units] a Example design chart for cost-effective embankment warrants based on traffic speeds and volumes, slope geometry and length of slope (metric units) b Example design chart for cost-effective embankment warrants based on traffic speeds and volumes, slope geometry and length of slope [U.S. customary units] Definition of roadside barriers xvii

10 Figure Title 5.5 Three-strand cable barrier Weak post W-beam barrier Ironwood aesthetic guardrail Weak post box beam barrier Steel post W-beam with wood block-outs Wood post W-beam with wood block-outs Wood post thrie-beam barrier Modified thrie-beam guardrail Merritt Parkway aesthetic guardrail Steel-backed timber guardrail New Jersey safety-shape barrier Ontario tall wall median barrier mm [90 in.] New Jersey barrier Stone masonry wall Precast masonry wall Long-span, double-nested W-beam guardrail Recommended barrier placement for optimum performance Design parameters for vehicle encroachments on embankments Recommended barrier location on 1V:6H Approach barrier layout variables a Example design chart for a flared roadside barrier installation (metric units) b Example design chart for a flared roadside barrier installation [U.S. customary units] a Example design chart for a parallel roadside barrier installation (metric units) b Example design chart for a parallel roadside barrier installation [U.S. customary units] Approach barrier layout for opposing traffic Suggested roadside slopes for approach barriers Example of barrier design for bridge approach Example of barrier design for bridge piers Example of barrier design for non-traversable embankments Example of barrier design for fixed object on horizontal curve [U.S. customary units] Guidelines for median barriers on high-speed, fully controlled-access roadways Weak-post, W-beam median barrier Three-strand cable median barrier Brifen Wire Rope Safety Fence The Cable Safety System (CASS) U.S. High-Tension Cable System Safence Cable Barrier System Gibraltar Cable Barrier System Box-beam median barrier Strong-post W-beam median barrier Modified thrie-beam median barrier Concrete safety-shape median barrier xviii

11 Figure Title 6.13 New York retrofit of concrete barrier Single-slope concrete median barrier Quickchange moveable barrier system Barrier termination at permanent openings BarrierGate Recommended barrier placement in non-level medians Example of a split median barrier layout Suggested layout for shielding a rigid object in a median Side-mounted, thrie-beam bridge railing Wyoming two-tube bridge railing Massachusetts S3 steel bridge railing BR27C on sidewalk Tall concrete safety-shape railing Texas Type TT (Tank Truck) railing End treatment for traffic railing on a bridge in low-speed situations Terminating traffic barrier on bridge with end terminal Inadequate railing strength Lack of continuity in railing Snagging potential Presence of brush curb Iowa concrete block retrofit bridge railing Thrie-beam retrofit (New York) Metal post and beam retrofit Possible solution to intersection side road near bridge W-beam transition to vertical concrete rail W-beam transition to modified concrete safety shape Thrie-beam transition to modified concrete safety shape a Thrie-beam transition to curb-mounted steel post and beam bridge railing b Thrie-beam transition to curb-mounted steel post and beam bridge railng Grading for flared guardrail end treatment Grading for non-flared guardrail end treatment Three-strand cable terminal Wyoming box beam end terminal Barrier anchored in backslope W-beam guardrail anchored in backslope Eccentric loader terminal Plan layout for eccentric loader terminal Slotted rail terminal (SRT-350) with 1.2 m [4 ft] flare Slotted rail terminal (SRT-350) with 0.9 m [3 ft] flare REGENT Vermont low-speed, W-beam guardrail end terminal Flared Energy-Absorbing Terminal (FLEAT) Beam Eating Steel Terminal (BEST) xix

12 Figure Title 8.15 Extruder Terminal (ET-2000) Sequential Kinking Terminal (SKT-350) QuadTrend Narrow Energy-Absorbing Terminal (NEAT) Sloped concrete end treatment Crash cushion applications Kinetic energy principal Advanced Dynamic Impact Extension Module (ADIEM II) Brakemaster Crash Cushion Attenuating Terminal (CAT) Bullnose guardrail system ABSORB 350 crash cushion QuadGuard QuardGuard LMC QuadGuard Elite Trinity Attenuating Crash Cushion (TRACC) Reusable Energy-Absorbing Crash Terminal (REACT 350) Narrow Connecticut Impact Attenuation System (NCAIS) Conservation of momentum principal The Fitch System The Energite System The TrafFix System Suggested layout for the last three exterior modules in an inertial barrier Dragnet Iowa Temporary Concrete Barrier Rockingham Precast Concrete Barrier J-J Hooks Portable Concrete Barrier Modified Virginia DOT Portable Concrete Barrier GPLINK Precast Temporary Concrete Barrier Georgia Temporary Concrete Barrier Idaho 20-ft New Jersey Portable Barrier California K-Rail (PCB) for semi-permanent installations Pin and Loop Joint Channel Splice Joint Vertical I-Beam Joint Lapped Joint J-Hook Joint Quickchange Barrier System Low-Profile Barrier System Triton Barrier GUARDIAN Safety Barrier System Timber Barrier Curb/Rail System Low-Profile Barrier Sloped End xx

13 Figure Title 9.20 PCB Steel Plate Transition QuadGuard CZ TRACC REACT 350 CZ Connecticut Impact Attenuation System Example energy-absorbing cartridge mounted in a frame (Ren-Gard 815) Example Energy-absorbing cartridge mounted in a frame (ALPHA 100K) Example Telescoping steel frame with a cutter assembly (MPS-350) Example Steel or polyethylene cylinder assembly (Vanderbilt TMA) Cones and Tubular Markers Portable Vertical Panel Drum Type II Plywood and Metal Panel Barricade (bent) Type III Wood and Steel Barricade Type III (Skid-Type) Barricade with perforated square tubing support Longitudinal Channelizing Barricades Wood, H-Leg Design Sign Support Minnesota s Perforated Steel Square Tube (PSST) Type III Barricade Sign Support with aluminum panels Montana Sign Support X-Base Sign Support Typical single mailbox installations Examples of hazardous single mailbox installations Examples of hazardous multiple mailbox installations Suggested minimum clearance distance to nearest mailbox in mailstops at intersections Mailbox turnout Mailbox support hardware, Series A Single and double mailbox assemblies, Series A Mailbox support hardware, Series B Single and double mailbox assemblies, Series B Single and double mailbox assemblies, Series C Collection unit on auxillary lane (top) and neighborhood delivery and collection box units Cantilever mailbox supports Breakaway cantilever mailbox supports Minnesota swing-away mailbox xxi

14 List of Tables Table Title 1.1 First harmful event fixed-object fatalities by object type Clear-zone distances in meters [feet] from edge of through traveled way Horizontal Curve Adjustments Barrier warrants for non-traversable terrain and roadside obstacles Roadside barriers and approved test levels Selection criteria for roadside barriers Summary of maximum deflections Suggested shy line offset (L S ) values a Example bumper trajectory data (metric units) b Example bumper trajectory data [U.S. customary units] Suggested flare rates for barrier design Suggested runout lengths for barrier design Roadside barrier inspection checklist Crashworthy end treatments Crashworthy crash cushions Sample design calculation for a sand-filled barrel system Reserve areas for gores Comparative maintenance requirements Example of clear-zone widths for work zones Temporary longitudinal barriers Suggested priorities for application of protective vehicles and truck mounted attenuators Example of guidelines for spacing of Shadow Vehicles Percentage of single vehicle run-off-the-road crashes by severity and time period for urban principal and minor arterials in Illinois Suggested guidelines for lateral placement of mailboxes xxii