TABLE OF CONTENTS --
CHAPTER 1 NEW FRAMEWORK FOR GEOMETRIC DESIGN --
1.1 INTRODUCTION --
1.2 PROJECT PURPOSE AND NEED --
1.3 OVERVIEW OF THE NEW FRAMEWORK FOR GEOMETRIC DESIGN --
1.4 FUNCTIONAL CLASSIFICATION FOR MOTOR VEHICLES --
1.4.1 Hierarchy of Motor Vehicle Movement --
1.4.2 Access Control and Mobility Needs --
1.4.3 Functional System Characteristics --
1.4.3.1 Definitions of Urban and Rural Areas --
1.4.3.2 Functional Categories --
1.4.3.3 Functional Systems for Rural Areas --
1.4.3.3.1 Rural Principal Arterial System --
1.4.3.3.2 Rural Minor Arterial System --
1.4.3.3.3 Rural Collector System --
1.4.3.3.4 Rural Local Road System --
1.4.3.4 Functional Systems for Urban Areas --
1.4.3.4.1 Urban Principal Arterial System --
1.4.3.4.2 Urban Minor Arterial Street System --
1.4.3.4.3 Urban Collector Street System --
1.4.3.4.4 Urban Local Street System --
1.4.4 Functional Classification as a Design Type --
1.5 CONTEXT CLASSIFICATION FOR GEOMETRIC DESIGN --
1.5.1 Context Classes for Roads and Streets in Rural Areas --
1.5.1.1 Rural Context --
1.5.1.2 Rural Town Context --
1.5.2 Context Classes for Roads and Streets in Urban Areas --
1.5.2.1 Suburban Context --
1.5.2.2 Urban Context --
1.5.2.3 Urban Core Context --
1.5.3 Design Guidance for Specific Context Classes --
1.6 MULTIMODAL CONSIDERATIONS --
1.6.1 Road and Street User Groups/Transportation Modes --
1.6.1.1 Automobiles --
1.6.1.2 Bicyclists --
1.6.1.3 Pedestrians --
1.6.1.4 Transit --
1.6.1.5 Trucks --
1.6.2 Consideration of All Transportation Modes in Design --
1.7 DESIGN PROCESS TO ADDRESS SPECIFIC PROJECT TYPES --
1.7.1 New Construction Projects --
1.7.2 Reconstruction Projects --
1.7.3 Construction Projects on Existing Roads --
1.8 DESIGN FLEXIBILITY --
1.9 PERFORMANCE-BASED DESIGN --
1.10 REFERENCES --
CHAPTER 2 DESIGN CONTROLS AND CRITERIA --
2.1 INTRODUCTION --
2.2 DRIVER PERFORMANCE AND HUMAN FACTORS --
2.2.1 Introduction --
2.2.2 Older Drivers and Older Pedestrians --
2.2.3 The Driving Task --
2.2.4 The Guidance Task --
2.2.4.1 Lane Placement and Road Following --
2.2.4.2 Car Following 2-3 2.2.4.3 Passing Maneuvers --
2.2.4.4 Other Guidance Activities --
2.2.5 The Information System --
2.2.5.1 Traffic Control Devices --
2.2.5.2 The Roadway and Its Environment --
2.2.6 Information Handling --
2.2.6.1 Reaction Time --
2.2.6.2 Primacy --
2.2.6.3 Expectancy --
2.2.7 Driver Error --
2.2.7.1 Errors Due to Driver Deficiencies --
2.2.7.1.1 Older Drives ---
2.2.7.2 Errors Due to Situation Demands --
2.2.8 Speed and Design --
2.2.9 Design Assessment --
2.3 TRAFFIC CHARACTERISTICS --
2.3.1 General Considerations --
2.3.2 Volume --
2.3.2.1 Average Daily Traffic --
2.3.2.2 Design Hour Traffic: Rural Areas --
2.3.2.3 Design Hour Traffic: Urban Areas --
2.3.3 Directional Distribution --
2.3.4 Composition of Traffic --
2.3.5 Projection of Future Traffic Demands --
2.3.6 Speed --
2.3.6.1 Operating Speed --
2.3.6.2 Running Speed --
2.3.6.3 Design Speed --
2.3.7 Traffic Flow Relationships --
2.4 HIGHWAY CAPACITY --
2.4.1 General Characteristics --
2.4.2 Application --
2.4.3 Capacity as a Design Control --
2.4.3.1 Design Service Flow Rate versus Design Volume --
2.4.3.2 Measures of Congestion --
2.4.3.3 Relation between Congestion and Traffic Flow Rate --
2.4.3.4 Acceptable Degrees of Congestion --
2.4.4 Factors Other Than Traffic Volume That Affect Operating Conditions --
2.4.4.1 Roadway Factors --
2.4.4.2 Alignment --
2.4.4.3 Weaving Sections --
2.4.4.4 Ramp Terminals --
2.4A.5 Traffic Factors --
2.4.4.6 Peak Hour Factor --
2.4.5 Levels of Service --
2.4.6 Design Service Flow Rates --
2.4.6.1 Weaving Sections --
2.4.6.2 Multilane Highways without Access Control --
2.4.6.3 Arterial Streets and Highways in Urban Areas --
2.4.6.4 intersections --
2.5 ACCESS CONTROL AND ACCESS MANAGEMENT --
2.5.1 General Conditions --
2.5.2 Basic Principles of Access Management --
2.5.3 Access Classifications --
2.5.4 Methods of Controlling Access --
2.5.5 Benefits of Controlling Access --
2.6 PEDESTRIANS --
2.6.1 General Considerations --
2.6.2 General Characteristics --
2.6.3 Walking Speeds --
2.6.4 Walkway Level of Service --
2.6.5 Intersections --
2.6.6 Reducing Pedestrian—Vehicular Conflicts --
2.6.7 Accommodating Persons with Disabilities --
2.6.7.1 Mobility Disabilities --
2.6.7.2 Vision Disabilities --
2.6.7.3 Cognitive Disabilities --
2.6.7.4 Hearing Disabilities --
2.7 BICYCLISTS --
2.8 DESIGN VEHICLES --
2.8.1 General Characteristics --
2.8.2 Minimum Turning Paths of Design Vehicles --
2.8.3 Vehicle Performance --
2.8.4 Vehicular Pollution --
2.9 SAFETY --
2.9.1 Key Factors Related to Traffic Crashes --
2.9.1.1 Roadway Design --
2.9.1.2 Roadside Design --
2.9.1.3 Traffic Control Devices --
2.9.2 Key Safety Resources --
2.9.3 Safety Improvement Programs --
2.9.4 Project Development Process --
2.10 ENVIRONMENT --
2.11 REFERENCES --
CHAPTER 3 ELEMENTS OF DESIGN --
3.1 INTRODUCTION --
3.2 SIGHT DISTANCE --
3.2.1 General Considerations --
3.2.2 Stopping Sight Distance --
3.2.2.1 Brake Reaction Time --
3.2.2.2 Braking Distance --
3.2.2.3 Design Values --
3.2.2.4 Effect of Grade on Stopping --
3.2.2.5 Variation for Trucks --
3.2.2.5.1 New Construction vs. Projects on Existing Roads --
3.2.3 Decision Sight Distance --
3.2.4 Passing Sight Distance for Two-Lane Highways --
3.2.4.1 Criteria for Design --
3.2.4.2 Design Values --
3.2.4.3 Effect of Grade on Passing Sight Distance --
3.2.4.4 Frequency and Length of Passing Sections --
3.2.5 Sight Distance for Multilane Highways --
3.2.6 Criteria for Measuring Sight Distance --
3.2.6.1 Height of Driver's Eye --
3.2.6.2 Height of Object --
3.2.6.3 Sight Obstructions --
3.2.6.4 Measuring Sight Distance --
3.3 HORIZONTAL ALIGNMENT --
3.3.1 Theoretical Considerations --
3.3.2 General Considerations --
3.3.2.1 Superelevation --
3.3.2.2 Side Friction Factor --
3.3.2.3 Distribution of e and f over a Range of Curves --
3.3.3 Design Considerations --
3.3.3.1 Normal Cross Slope --
3.3.3.2 Maximum Superelevation Rates for Streets and Highways --
3.3.3.3 Minimum Radius --
3.3.3.4 Effects of Grades --
3.3.4 Design for Rural Highways, Urban Freeways, and High-Speed Urban Streets --
3.3.4.1 Side Friction Factors --
3.3.4.2 Superelevation --
3.3.4.3 Procedure for Development of Method 5 Superelevation Distribution --
3.3.5 Design Superelevation Tables --
3.3.5.1 Minimum Radius of Curve for Section with Normal Crown --
3.3.6 Design for Low-Speed Urban Streets --
3.3.6.1 Side Friction Factors --
3.3.6.2 Superelevation --
3.3.7 Turning Roadways --
3.3.7.1 Design Speed --
3.3.7.2 Maximum Superelevation for Turning Roadways --
3.3.7.3 Use of Compound Curves --
3.3.8 Transition Design Controls --
3.3.8.1 General Considerations --
3.3.8.2 Tangent-to-Curve Transition --
3.3.8.2.1 Minimum Length of Superelevation Runoff --
3.3.8.2.2 Minimum Length of Tangent Runout --
3.3.8.2.3 Location with Respect to End of Curve --
3.3.8.2.4 Limiting Superelevation Rates --
3.3.8.3 Spiral Curve Transitions --
3.3.8.4 Length of Spiral --
3.3.8.4.1 Length of Spiral --
3.3.8.4.2 Maximum Radius for Use of a Spiral --
3.3.8.4.3 Minimum Length of Spiral --
3.3.8.4.4 Maximum Length of Spiral --
3.3.8.4.5 Desirable Length of Spiral --
3.3.8.4.6 Length of Superelevation Runoff --
3.3.8.4.7 Limiting Superelevation Rates --
3.3.8.4.8 Length of Tangent Runout --
3.3.8.4.9 Location with Respect to End of Curve --
3.3.8.5 Compound Curve Transition --
3.3.8.6 Methods of Attaining Superelevation --
3.3.8.7 Design of Smooth Profiles for Traveled-Way Edges --
3.3.8.8 Axis of Rotation with a Median --
3.3.8.8.1 Case I --
3.3.8.8.2 Case II --
3.3.8.8.3 Case III --
3.3.8.8.4 Divided Highway --
3.3.8.9 Minimum Transition Grades and Drainage Considerations --
3.3.8.10 Transitions and Compound Curves for Turning Roadways --
3.3.8.11 Length of Spiral for Turning Roadways --
3.3.8.12 Compound Circular Curves --
3.3.9 Offtracking --
3.3.9.1 Derivation of Design Values for Widening on Horizontal Curves --
3.3.10 Traveled-Way Widening on Horizontal Curves --
3.3.10.1 Design Values for Traveled-Way Widening --
3.3.10.2 Application of Widening on Curves --
3.3.11 Widths for Turning Roadways at Intersections --
3.3.11.1 Three Cases --
3.3.11.1.1 Case I --
3.3.11.1.2 Case II --
3.3.11.1.3 Case Ill --
3.3.11.2 Design Values --
3.3.11.3 Widths Outside the Traveled Way --
3.3.12 Sight Distance on Horizontal Curves --
3.3.12.1 Stopping Sight Distance --
3.3.12.2 Passing Sight Distance --
3.3.13 General Controls for Horizontal Alignment --
3.4 VERTICAL ALIGNMENT --
3.4.1 Terrain --
3.4.2 Grades --
3.4.2.1 Vehicle Operating Characteristics on Grades --
3.4.2.1.1 Passenger Cars --
3.4.2.1.2 Trucks --
3.4.2.1.3 Recreational Vehicles --
3.4.2.2 Control Grades for Design --
3.4.2.2.1 Maximum Grades --
3.4.2.2.2 Minimum Grades --
3.4.2.2.3 Pedestrian Considerations --
3.4.2.3 Critical Lengths of Grade for Design --
3.4.3 Climbing Lanes --
3.4.3.1 Climbing Lanes for Two-Lane Highways --
3.4.3.1.1 General --
3.4.3.1.2 Trucks --
3.4.3.1.3 Summary --
3.4.3.2 Climbing Lanes on Freeways and Multilane Highways --
3.4.3.2.1 General --
3.4.3.2.2 Trucks --
3.4.4 Methods for Increasing Passing Opportunities on Two-Lane Roads --
3.4.4.1 Passing Lanes --
3.4.4.2 2+1 Roadways --
3.4.4.3 Turnouts --
3.4.4.4 Shoulder Driving --
3.4.4.5 Shoulder Use Sections --
3.4.5 Emergency Escape Ramps --
3.4.5.1 General --
3.4.5.2 Need and Location for Emergency Escape Ramps --
3.4.5.3 Types of Emergency Escape Ramps --
3.4.5.4 Design Considerations --
3.4.5.5 Brake-Check Areas --
3.4.5.6 Maintenance --
3.4.6 Vertical Curves --
3.4.6.1 General Considerations --
3.4.6.2 Crest Vertical Curves --
3.4.6.2.1 Design Controls: Stopping Sight Distance --
3.4.6.2.2 Design Controls: Passing Sight Distance --
3.4.6.3 Sag Vertical Curves --
3.4.6.4 Sight Distance at Undercrossings --
3.4.6.5 General Controls for Vertical Alignment --
3.5 COMBINATIONS OF HORIZONTAL AND VERTICAL ALIGNMENT--
3.5.1 General Considerations --
3.5.2 General Design Controls --
3.5.3 Alignment Coordination in Design --
3.6 OTHER FEATURES AFFECTING GEOMETRIC DESIGN --
3.6.1 Erosion Control and Landscape Development --
3.6.2 Rest Areas, Information Centers, and Scenic Overlooks --
3.6.3 Lighting --
3.6.4 Utilities --
3.6.4.1 General --
3.6.4.2 Rural Areas --
3.6.4.3 Urban Areas --
3.6.5 Traffic Control Devices --
3.6.5.1 Traffic Signs, Pavement Markings, and Traffic Signals --
3.6.5.2 Intelligent Transportation Systems --
3.6.6 Traffic Management Plans for Construction --
3.7 REFERENCES --
CHAPTER 4 CROSS-SECTION ELEMENTS --
4.1 GENERAL --
4.2 TRAVELED WAY --
4.2.1 Surface Type --
4.2.2 Cross Slope --
4.2.2.1 Rate of Cross Slope --
4.2.2.2 Weather Considerations --
4.2.2.3 Unpaved Surfaces --
4.2.3 Skid Resistance --
4.2.4 Hydroplaning --
4.3 LANE WIDTHS --
4.4 SHOULDERS --
4.4.1 General Characteristics --
4.4.2 Shoulder Width --
4.4.3 Shoulder Cross Sections --
4.4.4 Shoulder Stability --
4.4.5 Shoulder Contrast --
4.4.6 Turnouts --
4.5 RUMBLE STRIPS --
4.6 ROADSIDE DESIGN --
4.6.1 Clear Zones --
4.6.2 Lateral Offset --
4.7 CURBS --
4.7.1 General Considerations --
4.7.2 Curb Configurations --
4.7.2.1 Gutters --
4.7.3 Curb Placement --
4.8 DRAINAGE CHANNELS AND SIDESLOPES --
4.8.1 General Considerations --
4.8.2 Drainage --
4.8.3 Drainage Channels --
4.8.4 Sideslopes --
4.9 ILLUSTRATIVE OUTER CROSS SECTIONS --
4.9.1 Normal Crown Sections --
4.9.2 Superelevated Sections --
4.10 TRAFFIC BARRIERS --
4.10.1 General Considerations --
4.10.2 Longitudinal Barriers --
4.10.2.1 Roadside Barriers --
4.10.2.2 Median Barriers --
4.10.3 Bridge Railings --
4.10.4 Crash Cushions --
4.11 MEDIANS --
4.12 FRONTAGE ROADS --
4.13 OUTER SEPARATIONS --
4.14 ROADWAY TRAFFIC NOISE ABATEMENT --
4.14.1 General Considerations --
4.14.2 Noise Evaluation Procedures --
4.14.3 Noise Reduction --
4.15 ROADSIDE CONTROL --
4.15.1 General Considerations --
4.15.2 Driveways --
4.15.3 Mailboxes --
4.15.4 Fencing --
4.16 TUNNELS --
4.16.1 General Considerations --
4.16.2 Types of Tunnels --
4.16.3 General Design Considerations --
4.16.4 Tunnel Sections --
4.16.5 Examples of Tunnels --
4.17 PEDESTRIAN FACILITIES --
4.17.1 Sidewalks -
4.17.2 Grade-Separated Pedestrian Crossings --
4.17.3 Curb Ramps --
4.18 BICYCLE FACILITIES --
4.19 TRANSIT FACILITIES --
4.19.1 Bus Turnouts on Freeways --
4.19.2 Bus Turnouts on Arterials --
4.19.3 Park-and-Ride Facilities --
4.19.3.1 Location --
4.19.3.2 Design --
4.20 ON-STREET PARKING --
4.21 REFERENCES --
CHAPTER 5 LOCAL ROADS AND STREETS --
5.1 INTRODUCTION --
5.2 LOCAL ROADS IN RURAL AREAS --
5.2.1 General Design Considerations --
5.2.1.1 Design Speed --
5.2.1.2 Design Traffic Volume --
5.2.1.3 Levels of Service --
5.2.1.4 Alignment --
5.2.1.5 Grades --
5.2.1.6 Cross Slope --
5.2.2 Cross-Sectional Elements --
5.2.2.1 Width of Roadway --
5.2.2.2 Number of Lanes --
5.2.2.3 Right-of-Way Width --
5.2.2.4 Medians --
5.2.2.5 Bicycle and Pedestrian Facilities --
5.2.2.6 Driveways --
5.2.2.7 Structures --
5.2.2.7.1 New and Reconstructed Structures --
5.2.2.7.2 Vertical Clearance --
5.2.2.8 Roadside Design --
5.2.2.8.1 Clear Zones --
5.2.2.8.2 Lateral Offset --
5.2.2.8.3 Foreslopes --
5.2.2,9 Intersection Design --
5.2.2.10 Railroad—Highway Grade Crossings --
5.2.2.11 Traffic Control Devices --
5.2.2.12 Drainage --
5.2.2.13 Erosion Control and Landscaping --
5.3 LOCAL STREETS IN URBAN AREAS --
5.3.1 General Design Considerations --
5.3.1.1 Design Speed --
5.3.1.2 Design Traffic Volume --
5.3.1.3 Levels of Service --
5.3.1.4 Alignment --
5.3.1.5 Grades --
5.3.1.6 Cross Slope --
5.3.1.7 Superelevation --
5.3.1.8 Sight Distance --
5.3.2 Cross-Sectional Elements --
5.3.2.1 Width of Traveled Way --
5.3.2.2 Number of Lanes --
5.3.2.3 Parking Lanes --
5.3.2.4 Medians --
5.3.2.5 Curbs --
5.3.2.6 Right-of-Way Width --
5.3.2.7 Provision for Utilities --
5.3.2.8 Border Area --
5.3.2.9 Bicycle and Pedestrian Facilities --
5.3.2.10 Cul-de-Sacs and Turnarounds --
5.3.2.11 Alleys --
5.3.2.12 Driveways --
5.3.3 Structures --
5.3.3.1 New and Reconstructed Structures --
5.3,3.2 Vertical Clearance --
5.3.4 Roadside Design --
5.3.4.1 Clear Zones --
5.3.4.2 Lateral Offset --
5.3.5 Intersection Design --
5.3.6 Railroad—Highway Grade Crossings --
5.3.7 Traffic Control Devices --
5.3.8 Roadway Lighting --
5.3.9 Drainage --
5.3.10 Erosion Control --
5.3.11 Landscaping --
5.4 RECREATIONAL ROADS --
5.4.1 General Design Considerations --
5.4.1.1 Design Speed --
5.4.1.2 Design Vehicle --
5.4.1.3 Grades --
5.4.1.4 Vertical Alignment --
5.4.1.5 Horizontal Alignment and Superelevation --
5.4.1.6 Sight Distance --
5.4.1.7 Passing Sight Distance --
5.4.1.8 Cross Slope --
5.4.2 Cross-Sectional Elements --
5.4.2.1 Width of Roadway --
5.4.2.2 Number of Lanes --
5.4.3 Structures --
5.4.4 Roadside Design --
5.4.4.1 Clear Zones --
5.4.4.2 Roadside Slopes --
5.4.4.3 Roadside Barriers --
5.4.5 Signing and Marking --
5.4.6 Bicycle and Pedestrian Facilities --
5.5 RESOURCE RECOVERY AND LOCAL SERVICE ROADS --
5.6 LOW-VOLUME ROADS --
5.7 REFERENCES --
CHAPTER 6 COLLECTOR ROADS AND STREETS --
6.1 INTRODUCTION --
6.2 COLLECTORS IN RURAL AREAS --
6.2.1 General Design Considerations --
6.2.1.1 Design Speed --
6.2.1.2 Design Traffic Volumes --
6.2.1.3 Level of Service --
6.2.1.4 Alignment --
6.2.1.5 Grades --
6.2.1.6 Cross Slope --
6.2.1.7 Superelevation --
6.2.1.8 Sight Distance --
6.2.2 Cross-Sectional Elements --
6.2.2.1 Width of Roadway --
6.2.2.2 Number of Lanes --
6.2.2.3 Parking Lanes --
6.2.2.4 Medians --
6.2.2.5 Right-of-Way Width --
6.2.2.6 Bicycle/Pedestrian Facilities --
6.2.3 Structures --
6.2.3.1 New and Reconstructed Structures --
6.2.3.2 Vertical Clearance --
6.2.4 Roadside Design --
6.2.4.1 Clear Zones --
6.2.4.2 Lateral Offset --
6.2.4.3 Foreslopes --
6.2.5 Intersection Design --
6.2.6 Railroad—Highway Grade Crossings --
6.2.7 Traffic Control Devices --
6.2.8 Drainage --
6.2.9 Erosion Control and Landscaping --
6.2.10 Speed Transitions Entering Rural Towns --
6.2.11 Design of Collectors in the Rural Town Context --
6.3 COLLECTORS IN URBAN AREAS --
6.3.1 General Design Considerations --
6.3.1.1 Design Speed --
6.3.1.2 Design Traffic Volumes --
6.3.1.3 Level of Service --
6.3.1.4 Alignment --
6.3.1.5 Grades --
6.3.1.6 Cross Slope --
6.3.1.7 Superelevation --
6.3.1.8 Sight Distance --
6.3.2 Cross-Sectional Elements --
6.3.2.1 Width of Roadway --
6.3.2.2 Number of Lanes --
6.3.2.3 Parking Lanes --
6.3.2.4 Medians--
6.3.2.5 Curbs --
6.3.2.6 Right-of-Way Width --
6.3.2.7 Provision for Utilities--
6.3.2.8 Border Area --
6.3.2.9 Bicycle/Pedestrian Facilities --
6.3.2.10 Driveways --
6.3.3 Structures --
6.3.3.1 New and Reconstructed Structures --
6.3.3.2 Vertical Clearance --
6.3.4 Roadside Design --
6.3.4.1 Clear Zones --
6.3.4.2 Lateral Offset --
6.3.5 Intersection Design --
6.3.6 Railroad—Highway Grade Crossings --
6.3.7 Traffic Control Devices --
6.3.8 Roadway Lighting --
6.3.9 Drainage --
6.3.10 Erosion Control --
6.3.11 Landscaping --
6.4 REFERENCES --
CHAPTER 7 ARTERIAL ROADS AND STREETS --
7.1 INTRODUCTION -
7.2 ARTERIALS IN RURAL AREAS --
7.2.1 General Characteristics --
7.2.2 General Design Considerations --
7.2.2.1 Design Speed --
7_3 .7:33 Design Traffic Volumes --
7.2.2.3 Level of Service --
7.2.2.4 Sight Distance --
7.2.2.5 Alignment --
7.2.2.6 Grades --
7.2.2.7 Cross Slope --
7.2.2.8 Superelevation --
7.2.3 Cross-Sectional Elements --
7.2.3.1 Roadway Width --
7.2.3.2 Number of Lanes --
7.2.3.3 Cross Section and Right-of-Way --
7.2.4 Roadside Design --
7.2.4.1 Clear Zones --
7.2.4.2 Lateral Offset --
7.2.5 Structures --
7.2.5.1 Vertical Clearances --
7.2.6 Traffic Control Devices --
7.2.7 Erosion Control --
7.2.8 Provision for Passing --
7.2.9 Ultimate Development of Multilane Divided Arterials in Rural --
7.2.10 Multilane Undivided Arterials in Rural Areas --
7.2.11 Divided Arterials in Rural Areas --
7.2.11.1 General Features --
7.2.11.2 Lane Widths --
7.2.11.3 Cross Slope --
7.2.11.4 Shoulders --
7.2.11.5 Median Barrier Clearance --
7.2.11.6 Medians --
7.2.11.7 Alignment and Profile --
7.2.11.8 Climbing Lanes on Multilane Arterials in Rural Areas --
7.2.11.9 Superelevated Cross Sections --
7.2.11.10 Cross Section and Right-of-Way Widths --
7.2.11.11 Sections with Widely Separated Roadways --
7.2.12 Intersections --
7.2.13 Access Management --
7.2.14 Bicycle and Pedestrian Facilities --
7.2.15 Bus Turnouts --
7.2.16 Railroad—Highway Grade Crossings --
7.2.17 Lighting --
7.2.18 Rest Areas --
7.2.19 Speed Transitions Entering Rural Towns --
7.2.20 Design of Arterials in the Rural Town Context --
7.3 ARTERIALS IN URBAN AREAS --
7.3.1 General Characteristics --
7.3.2 General Design Considerations --
7.3.2.1 Design Speed --
7.3.2.2 Design Traffic Volumes --
7.3.2.3 Level of Service --
7.3.2.4 Sight Distance --
7.3.2.5 Alignment --
7.3.2.6 Grades --
7.3.2.7 Superelevation --
7.3.2.8 Cross Slope --
7.3.3 Cross-Sectional Elements --
7.3.3.1 Roadway Widths --
7.3.3.2 Lane Widths --
7.3.3.3 Curbs and Shoulders --
7.3.3.4 Number of Lanes --
7.3.3.5 Medians --
7.3.3.6 Drainage --
7.3.3.7 Parking Lanes --
7.3.3.8 Borders and Sidewalks --
7.3.3.9 Right-of-Way Width --
7.3.4 Roadside Design --
7.3.4.1 Clear Zones --
7.3.4.2 Lateral Offset --
7.3.5 Structures --
7.3.5.1 New and Reconstructed Structures --
7.3.5.2 Vertical Clearances --
7.3.6 Traffic Barriers --
7.3.7 Railroad—Highway Grade Crossings --
7.3.8 Access Management --
7.3.8.1 General Features --
7.3.8.2 Access Control by Statute --
7.3.8.3 Access Control by Zoning --
7.3.8.4 Access Control through Driveway Regulations --
7.3.8.5 Access Control through Geometric Design --
7.3.9 Bicycle and Pedestrian Facilities --
7.3.9.1 Bicycle Facilities --
7.3.9.2 Pedestrian Facilities --
7.3.10 Provision for Utilities --
7.3.11 Intersection Design --
7.3.12 Operational Control --
7.3.12.1 Traffic Control Devices --
7.3.12.2 Provision and Management of Curb Parking --
7.3.13 Speed Management in Design --
7.3.14 Directional Lane Usage --
7.3.14.1 One-Way Operation --
7.3.14.2 Reverse-Flow Operation --
7.3.15 Frontage Roads and Outer Separations --
7.3.16 Grade Separations and Interchanges --
7.3.17 Erosion Control --
7.3.18 Lighting --
7.3.19 Public Transit Facilities --
7.3.19.1 Location of Bus Stops --
7.3.19.2 Bus Turnouts --
7.3.19.3 Reserved Bus Lanes --
7.3.19.4 Traffic Control Measures --
7.4 REFERENCES --
CHAPTER 8 FREEWAYS --
8.1 INTRODUCTION --
8.2 GENERAL DESIGN CONSIDERATIONS --
8.2.1 Design Speed --
8.2.2 Design Traffic Volumes --
8.2.3 Levels of Service --
8.2.4 Traveled Way and Shoulders --
8.2.5 Curbs --
8.2.6 Superelevation --
8.2.7 Grades --
8.2.8 Structures --
8.2.9 Vertical Clearance --
8.2.10 Roadside Design --
8.2.11 Ramps and Terminals --
8.2.12 Outer Separations, Borders, and Frontage Roads --
8.3 FREEWAYS IN RURAL AREAS --
8.3.1 Alignment and Profile --
8.3.2 Medians --
8.3.3 Sideslopes --
8.3.4 Frontage Roads --
8.4 FREEWAYS IN URBAN AREAS --
8.4.1 General Design Characteristics--
8.4.2 Medians --
8.4.3 Depressed Freeways --
8.4.3.1 General Characteristics --
8.4.3.2 Slopes and Walls --
8.4.3.3 Typical Cross Section --
8.4.3.4 Restrictive Cross Section --
8.4.3.5 Walled Cross Section --
8.4.3.6 Example of Depressed Freeway --
8.4.4 Elevated Freeways --
8.4.4.1 General Characteristics --
8.4.4.2 Medians --
8.4.4.3 Ramps and Terminals --
8.4.4.4 Frontage Roads --
8.4.4.5 Building Offset --
8.4.4.6 Typical Cross Section --
8.4.4.7 Freeways on Earth Embankment --
8.4.4.8 Examples of Elevated Freeways --
8.4.5 Ground-Level Freeways --
8.4.5.1 General Characteristics --
8.4.5.2 Typical Cross Section --
8.4.5.3 Restrictive Cross Section --
8.4.5.4 Example of a Ground-Level Freeway --
8.4.6 Combination-Type Freeways --
8.4.6.1 General Characteristics --
8.4.6.2 Profile Control --
8.4.6.2.1 Rolling Terrain --
8.4.6.2.2 Level Terrain --
8.4.6.3 Cross-Section Control --
8.4.7 Special Freeway Designs --
8.4.7.1 Reverse-Flow Roadways --
8.4.7.2 Dual-Divided Freeways --
8.4.7.3 Freeways with Collector—Distributor Roads --
8.4.8 Accommodation of Managed Lanes and Transit Facilities --
8.4.8.1 General Considerations --
8.4.8.2 Buses --
8.4.8.2.1 Exclusive HOV Lanes --
8.4.8.2.2 Bus Stops --
8.4.8.2.3 Bus-Stop Arrangements --
8.4.8.2.4 Bus Stops at Freeway Level --
8.4.8.2.5 Bus Stops at Street Level --
8.4.8.2.6 Stairs, Ramps, Escalators, and Elevators --
8.4.8.3 Rail Transit --
8.4.8.3.1 Typical Sections --
8.4.8.3.2 Stations --
8.4.8.3.3 Example of Rail Transit Combined with a Freeway --
8.5 REFERENCES --
CHAPTER 9 INTERSECTIONS --
9.1 INTRODUCTION --
9.2 GENERAL DESIGN CONSIDERATIONS AND OBJECTIVES --
9.2.1 Characteristics of Intersections --
9.2.2 Intersection Functional Area --
9.2.3 Design Objectives --
9.2.4 Design Considerations for Intersection User Groups --
9.2.5 Intersection Capacity --
9.2.6 Intersection Design Elements --
9.3 TYPES AND EXAMPLES OF INTERSECTIONS --
9.3.1 Three-Leg Intersections --
9.3.1.1 Basic Types of Intersections --
9.3.1.2 Channelized Three-Leg Intersections --
9.3.2 Four-Leg Intersections --
9.3.2.1 Basic Types --
9.3.2.2 Channelized Four-Leg Intersections --
9.3.3 Multileg Intersections --
9.3.4 Roundabouts --
9.3.4.1 Mini-Roundabouts --
9.3.4.2 Single-Lane Roundabouts --
9.3.4.3 Multilane Roundabouts --
9.4 ALIGNMENT AND PROFILE --
9.4.1 General considerations --
9.4.2 Alignment --
9.4.3 Profile --
9.5 INTERSECTION SIGHT DISTANCE --
9.5.1 General Considerations --
9.5.2 Sight Triangles --
9.5.2.1 Approach Sight Triangles --
9.5.2.2 Departure Sight Triangles --
9.5.2.3 Identification of Sight Obstructions within Sight Triangles --
9.5.3 Intersection Control --
9.5.3.1 Case A—Intersections with No Control --
9.5.3.2 Case B—Intersections with Stop Control on the Minor Road --
9.5.3.2.1 Case B1—Left Turn from the Minor Road --
9.5.3.2.2 Case B2—Right Turn from the Minor Road --
9.5.3.2.3 Case B3—Crossing Maneuver from the Minor Road --
9.5.3.3 Case C—Intersections with Yield Control on the Minor Road --
9.5.3.3.1 Case C1—Crossing Maneuver from the Minor Road --
9.5.3.3.2 Case C2—Left- and Right-Turn Maneuvers --
9.5.3.4 Case D--Intersections with Traffic Signal Control --
9.5.3.5 Case E--Intersections with All-Way Stop Control --
9.5.3.6 Case F—Left Turns from the Major Road --
9.5.3.7 Case G--Roundabouts --
9.5.4 Effect of Skew --
9.6 TURNING ROADWAYS AND CHANNELIZATION --
9.6.1 Turning Roadways --
9.6.1.1 General --
9.6.1.2 Channelized Right-Turn Lanes --
9.6.1.3 Design Considerations --
9.6.1.4 Curb Radius --
9.6.2 Channelization --
9.6.3 Islands --
9.6.3.1 General Characteristics --
9.6.3.2 Channelizing Islands --
9.6.3.3 Divisional Islands --
9.6.3.4 Refuge Islands --
9.6.3.5 Island Size and Designation --
9.6.3.6 Island Delineation and Approach Treatment --
9.6.3.7 Corner Islands for Turning Roadways --
9.6.4 Superelevation for Turning Roadways at Intersections--
9.6.4.1 General Design Guidelines --
9.6.4.2 Superelevation Runoff --
9.6.4.3 Development of Superelevation at Turning Roadway Terminals --
9.6.5 Stopping Sight Distance at Intersections for Turning Roadways --
9.6.5.1 General Considerations --
9.6.5.2 Vertical Control --
9.6.5.3 Horizontal Control --
9.7 AUXILIARY LANES --
9.7.1 General Design Considerations --
9.7.2 Deceleration Lanes --
9.7.2.1 Perception—Reaction Distance --
9.7.2.2 Storage Length --
9.7.2.3 Taper Length --
9.7.3 Design Treatments for Left-Turn Maneuvers --
9.7.3.1 Guidelines for Provision and Design of Left-Turn and Bypass Lanes --
9.7.3.2 Median Left-Turn Lanes --
9.7.3.3 Median End Treatment --
9.7.3.4 Offset Left-Turn Lanes --
9.7.3.5 Simultaneous Left Turns --
9.7.3.6 Double or Triple Left-Turn Lanes --
9.8 MEDIAN OPENINGS --
9.8.1 General Design Considerations --
9.8.2 Control Radii for Minimum Turning Paths --
9.8.2.1 Shape of Median End --
9.8.3 Effect of Skew --
9.8.4 Design Considerations for Higher Speed Left Turns --
9.9 INDIRECT LEFT TURNS AND U-TURNS --
9.9.1 General Design Considerations --
9.9.2 Intersections with Jughandle or Loop Roadways --
9.9.3 Displaced Left-Turn intersections --
9.9.4 Wide Medians with U-Turn Crossover Roadways --
9.9.5 Location and Design of U-Turn Median Openings--
9.10 ROUNDABOUT DESIGN --
9.10.1 Geometric Elements of Roundabouts --
9.10.1.1 Size and Space Needs --
9.10.2 Fundamental Principles --
9.10.2.1 Slow Speeds Using Deflection --
9.10.2.2 Lane Balance and Lane Continuity --
9.10.2.3 Appropriate Natural Path Alignment --
9.10.2.4 Design Vehicle --
9.10.2.5 Nonmotorized Users --
9.10.2.6 Sight Distance and Visibility --
9.11 OTHER INTERSECTION DESIGN CONSIDERATIONS --
9.11.1 Intersection Design Elements with Frontage Roads --
9.11.2 Traffic Control Devices --
9.11.3 Bicyclists --
9.11.4 Pedestrians --
9.11.5 Lighting --
9.11.6 Driveways --
9.11.7 Left Turns at Midblock Locations and at Unsignalized Intersections on Streets with Flush Medians --
9.12 RAILROAD—HIGHWAY GRADE CROSSINGS --
9.12.1 Horizontal Alignment --
9.12.2 Vertical Alignment --
9.12.3 Crossing Design --
9.12.4 Sight Distance --
9.13 REFERENCES --
CHAPTER 10 GRADE SEPARATIONS AND INTERCHANGES --
10.1 INTRODUCTION AND GENERAL TYPES OF INTERCHANGES --
10.2 WARRANTS FOR INTERCHANGES AND GRADE SEPARATIONS --
10.3 ADAPTABILITY OF HIGHWAY GRADE SEPARATIONS AND INTERCHANGES --
10.3.1 Traffic and Operation --
10.3.2 Site Conditions --
10.3.3 Type of Highway and Intersecting Facility --
10.4 ACCESS SEPARATIONS AND CONTROL ON THE CROSSROAD AT INTER-CHANGES --
10.5 SAFETY --
10.6 STAGE DEVELOPMENT --
10.7 ECONOMIC FACTORS --
10.7.1 Initial Costs --
10.7.2 Maintenance Costs --
10.7.3 Vehicular Operating Costs --
10.8 GRADE SEPARATION STRUCTURES --
10.8.1 Introduction --
10.8.2 Types of Separation Structures --
10.8.3 Overpass versus Underpass Roadways --
10.8.3.1 General Design Considerations --
10.8.3.2 Structure Widths --
10.8.4 Underpass Roadways --
10.8.4.1 Lateral Offset --
10.8.4.2 Vertical Clearance --
10.8.5 Overpass Roadways --
10.8.5.1 Bridge Railings --
10.8.5.2 Lateral Offset --
10.8.5.3 Medians --
10.8.6 Longitudinal Distance to Attain Grade Separation --
10.8.7 Grade Separations without Ramps --
10.9 INTERCHANGES --
10.9.1 General Considerations --
10.9.2 Three-Leg Designs --
10.9.3 Four-Leg Designs --
10.9.3.1 Ramps in One Quadrant --
10.9.3.2 Diamond Interchanges --
10.9.3.3 Roundabout Interchanges --
10.9.3.4 Single-Point Diamond Interchanges --
10.9.3.5 Diverging Diamond Interchanges --
10.9.3.6 Cloverleaf Interchanges --
10.9.3.6.1 Partial Cloverleaf Ramp Arrangements --
10.9.3.7 Directional Interchanges --
10.9.3.7.1 With Loops and Weaving --
10.9.3.7.2 With Loops and No Weaving --
10.9.3.7.3 Fully Directional --
10.9.4 Other Interchange Configurations --
10.9.4.1 Offset Interchanges --
10.9.4.2 Combination Interchanges --
10.9.5 General Design Considerations --
10.9.5.1 Determination of Interchange Configuration --
10.9.5.2 Approaches to the Structure --
10.9.5.2.1 Alignment, Profile, and Cross Section --
10.9.5.2.2 Sight Distance --
10.9.5.3 Interchange Spacing --
10.9.5.4 Uniformity of Interchange Patterns --
10.9.5.5 Route Continuity --
10.9.5.6 Overlapping Routes --
10.9.5.7 Signing and Marking --
10.9.5.8 Basic Number of Lanes --
10.9.5.9 Coordination of Lane Balance and Basic Number of Lanes --
10.9.5.10 Auxiliary Lanes --
10.9.5.11 Lane Reductions --
10.9.5.12 Weaving Sections --
10.9.5.13 Collector—Distributor Roads --
10.9.5.14 Two-Exit versus Single-Exit Interchange Design --
10.9.5.15 Wrong-Way Entry --
10.9.6 Ramps --
10.9.6.1 Types and Examples --
10.9.6.2 General Ramp Design Considerations --
10.9.6.2.1 Design Speed --
10.9.6.2.2 Portion of Ramp to Which Design Speed Is Applicable --
10.9.6.2.3 Ramps for Right Turns --
10.9.6.2.4 Loop Ramps --
10.9.6.2.5 Two-Lane Loop Ramps --
10.9.6.2.6 Semidirect Connections --
10.9.6.2.7 Direct Connections --
10.9.6.2.8 Different Design Speeds on Intersecting Highways --
10.9.6.2.9 At-Grade Terminals --
10.9.6.2.10 Curvature --
10.9.6.2.11 Sight Distance --
10.9.6.2.12 Grade and Profile Design --
10.9.6.2.13 Vertical Curves --
10.9.6.2.14 Superelevation and Cross Slope --
10.9,6.2.15 Gores --
10.9.6.3 Ramp Traveled-Way Widths --
10,9.6.3,1 Width and Cross Section --
10,9.6.3.2 Shoulder Widths and Lateral Offset --
10.9.6.3.3 Shoulders and Curbs --
10.9.6.4 Ramp Terminals --
10.9.6.4.1 Left-Side Entrances and Exits --
10.9.6.4.2 Terminal Location and Sight Distance --
10.9.6.4.3 Ramp Terminal Design --
10.9.6.4.4 Traffic Control --
10.9.6.4.5 Distance between a Free-Flow Terminal and Structure --
10.9.6.4.6 Distance between Successive Ramp Terminals --
10.9.6.4.7 Speed-Change Lanes --
10.9.6.5 Single-Lane Free-Flow Terminals, Entrances --
10.9.6.5.1 Taper-Type Entrances --
10.9.6.5.2 Parallel-Type Entrances --
10.9.6.6 Single-Lane Free-Flow Terminals, Exits --
10.9.6.6.1 Taper-Type Exits --
10.9.6.6.2 Parallel-Type Exits --
10.9.6.6.3 Free-Flow Terminals on Curves --
10.9.6.6.4 Multilane Free-Flow Terminals --
10.9.6.6.5 Two-Lane Entrances --
10.9.6.6.6 Two-Lane Exits --
10.9.6.6.7 Two-Lane Terminals on Curved Alignment --
10.9.6.6.8 Major Forks and Branch Connections --
10.9.7 Other Interchange Design Features --
10.9.7.1 Testing for Ease of Operation --
10.9.7.2 Pedestrian and Bicycle Accommodation --
10.9.7.3 Managed Lanes and Transit Facilities --
10.9.7.4 Ramp Metering --
10.9.7.5 Grading and Landscape Development --
10.9.7.5.1 Contour Grading Design --
10.9.7.5.2 Plantings --
10.9.7.6 Models --
10.10 REFERENCES.

LIST OF FIGURES --
CHAPTER 1 HIGHWAY FUNCTIONS --
Figure 1-1. Framework for Roadway Design Based on Functional Classification and Roadway Context --
Figure 1-2. Hierarchy of Movement --
Figure 1-3. Relationship of Functionally Classified Systems Serving Traffic Mobility and Land Access for Motor-Vehicle Traffic --
Figure 1-4. Typical Road in the Rural Context --
Figure 1-5. Typical Street in the Rural Town Context --
Figure 1-6. Typical Street in the Suburban Context --
Figure 1-7. Typical Street in the Urban Context --
Figure 1-8. Typical Street in the Urban Core Context --
CHAPTER 2 DESIGN CONTROLS AND CRITERIA --
Figure 2-1. Median Driver Reaction Time to Expected and Unexpected Information --
Figure 2-2. 85th-Percentile Driver Reaction Time to Expected and Unexpected Information --
Figure 2-3. Relation between Peak-Hour and Average Daily Traffic Volumes on Arterials in Rural Areas --
Figure 2-4. Generalized Speed-Volume-Density Relationships (44) --
Figure 2-5. Weaving Sections --
Figure 2-6. Simple and Multiple Weaving Sections --
Figure 2-7. Estimated Crash Rates by Type of Median—Urban and Suburban Areas (25) --
Figure 2-8. Estimated Crash Rates by Type of Median—Rural Areas (25) --
Figure 2-9. Estimated Crash Rates by Unsignalized and Signalized Access Density—Urban and Suburban Areas (25) --
Figure 2-10. Minimum Turning Path for Passenger Car (P) Design Vehicle --
Figure 2-11. Minimum Turning Path for Single-Unit Truck (SU-30 [SU-9]) Design Vehicle --
Figure 2-12. Minimum Turning Path for Single-Unit Truck (SU-40 [SU-12]) Design Vehicle --
Figure 2-13. Minimum Turning Path for Intercity Bus (BUS-40 [BUS-12]) Design Vehicle --
Figure 2-14. Minimum Turning Path for intercity Bus (BUS-45 [BUS-14]) Design Vehicle --
Figure 2-15. Minimum Turning Path for City Transit Bus (CITY-BUS) Design Vehicle --
Figure 2-16. Minimum Turning Path for Conventional School Bus (S-BUS-36 [S-BUS-11]) Design Vehicle --
Figure 2-17. Minimum Turning Path for Large School Bus (S-BUS-40 (5-BUS-12]) Design Vehicle --
Figure 2-18. Minimum Turning Path for Articulated Bus (A-BUS) Design Vehicle --
Figure 2-19. Turning Characteristics of a Typical Tractor—Semitrailer Combination Truck --
Figure 2-20. Computational Method for Determining the Centerline Turning Radius for Tractor—Semitrailer Combination Trucks --
Figure 2-21. Lengths of Commonly Used Truck Tractors --
Figure 2-22. Minimum Turning Path for Intermediate Semitrailer (WB-40 [WB-12]) Design Vehicle --
Figure 2-23. Minimum Turning Path for Interstate Semitrailer (WB-62 [WB-19]) Design Vehicle --
Figure 2-24. Minimum Turning Path for Interstate Semitrailer (WB-67 [WB-20]) Design Vehicle --
Figure 2-25. Minimum Turning Path for Double-Trailer Combination (WB-67D [WB-20D]) Design Vehicle --
Figure 2-26. Minimum Turning Path for Rocky Mountain Double-Trailer Combination (WB-92D [WB-28D]) Design Vehicle --
Figure 2-27. Minimum Turning Path for Triple-Trailer Combination (WB-100T [WB-30T1) Design Vehicle --
Figure 2-28. Minimum Turning Path for Turnpike-Double Combination (WB-109D [WB-33D]) Design Vehicle --
Figure 2-29. Minimum Turning Path for Motor Home (MH) Design Vehicle --
Figure 2-30. Minimum Turning Path for Passenger Car and Camper Trailer (P/T) Design Vehicle --
Figure 2-31. Minimum Turning Path for Passenger Car and Boat Trailer (P/B) Design Vehicle --
Figure 2-32. Minimum Turning Path for Motor Home and Boat Trailer (MH/B) Design Vehicle --
Figure 2-33. Acceleration of Passenger Cars, Level Conditions --
Figure 2-34. Deceleration Distances for Passenger Vehicles Approaching Intersections --
CHAPTER 3 ELEMENTS OF DESIGN --
Figure 3-1. Illustration of the Method for Measuring Sight Distance --
Figure 3-2. Geometry for Ball-Bank Indicator --
Figure 3-3. Side Friction Factors for Streets and Highways --
Figure 3-4. Side Friction Factors Assumed for Design --
Figure 3-5. Methods of Distributing Superelevation and Side Friction --
Figure 3-6. Method 5 Procedure for Development of the Superelevation Distribution --
Figure 3-7. Superelevation, Radius, and Design Speed for Low-Speed Street Design in Urban Areas --
Figure 3-8. Diagrammatic Profiles Showing Methods of Attaining Superelevation for a Curve to the Right --
Figure 3-9. Track Width for Widening of Traveled Way on Curves --
Figure 3-10. Front Overhang for Widening of Traveled Way on Curves --
Figure 3-11. Widening Components on Open Highway Curves (Two-Lane Highways,One-Way or Two-Way) --
Figure 3-12. Derivation of Turning Roadway Widths on Curves at Intersections --
Figure 3-13. Diagram Illustrating Components for Determining Horizontal Sight Distance --
Figure 3-14. Horizontal Sightline Offset (HSO) to Provide Stopping Sight Distance on Horizontal Curves --
Figure 3-15. Speed—Distance Curves for a Typical Heavy Truck of 140 lb/hp [85 kg/kW] for Deceleration on Upgrades --
Figure 3-16. Speed—Distance Curves for Acceleration of a Typical Heavy Truck of 140 lb/hp [85 kg/kW] on Upgrades and Downgrades --
Figure 3-17. Speed—Distance Curves for a Typical Heavy Truck of 200 lb/hp [120 kg/kW] for Deceleration on Upgrades --
Figure 3-18. Speed—Distance Curves for Acceleration of a Typical Heavy Truck of 200 lb/hp [ 120 kg/kW] on Upgrades and Downgrades --
Figure 3-19. Speed—Distance Curves for a Typical Recreational Vehicle on the Selected Upgrades (75) --
Figure 3-20. Crash Involvement Rate of Trucks for Which Running Speeds Are Reduced below Average Running Speed of All Traffic (25) --
Figure 3-21. Critical Lengths of Grade for Design, Assumed Typical Heavy Truck of 200 lb/hp [120 kg/kW], Entering Speed = 70 mph [110 km/h] --
Figure 3-22. Critical Lengths of Grade Using an Approach Speed of 55 mph [90 km/h) for TypicalRecreational Vehicle (23) --
Figure 3-23. Climbing Lanes on Two-Lane Highways --
Figure 3-24. Climbing Lane on Freeways and Multilane Highways --
Figure 3-25. Passing Lanes Sections on Two-Lane Roads --
Figure 3-26. Schematic for 2+1 Roadway --
Figure 3-27. Schematic for Three-Leg Intersection on a 2+1 Roadway --
Figure 3-28. Schematic for Four-Leg Intersection on a 2+1 Roadway --
Figure 3-29. Schematic for Adjacent Lane Drop Tapers on a 2+1 Roadway --
Figure 3-30. Schematic for Adjacent Lane Addition Tapers on a 2+1 Roadway --
Figure 3-31. Forces Acting on a Vehicle in Motion --
Figure 3-32. Basic Types of Emergency Escape Ramps --
Figure 3-33. Typical Emergency Escape Ramp --
Figure 3-34. Types of Vertical Curves --
Figure 3-35. Parameters Considered in Determining the Length of a Crest Vertical Curve to Provide --
Sight Distance --
Figure 3-36. Design Controls for Crest Vertical Curves—Open Road Conditions --
Figure 3-37. Design Controls for Sag Vertical Curves—Open Road Conditions --
Figure 3-38. Sight Distance at Undercrossings --
Figure 3-39. Vertical Clearance at Undercrossings --
Figure 3-40. Alignment and Profile Relationships in Roadway Design (43) --
CHAPTER 4 CROSS-SECTION ELEMENTS --
Figure 4-1. Typical Cross Section, Normal Crown --
Figure 4-2. Typical Cross Section, Superelevated --
Figure 4-3. Roadway Sections for Divided Highway (Basic Cross Slope Arrangements) --
Figure 4-4. Graded and Usable Shoulders --
Figure 4-5. Typical Highway Curbs --
Figure 4-6. Designation of Roadside Regions --
Figure 4-7. Typical Frontage Road Arrangements --
Figure 4-8. One-Way Frontage Roads, Entrance and Exit Ramps --
Figure 4-9. Typical Outer Separations for Various Types of Arterials --
Figure 4-10. Effects of Depressing the Roadway --
Figure 4-11. Effects of Elevating the Roadway --
Figure 4-12. Driveway Vertical Alignment and Profile Elements --
Figure 4-13. Typical Two-Lane Tunnel Sections --
Figure 4-14. Diagrammatic Tunnel Sections --
Figure 4-15. Entrance to a Freeway Tunnel --
Figure 4-16. Interior of a Two-Lane Directional Tunnel --
Figure 4-17. Typical Pedestrian Overpasses on Major Highways --
Figure 4-18. Curb Ramp Details --
Figure 4-19. Median Refuge --
Figure 4-20. Examples of Sidewalk Curb Ramps --
Figure 4-21. Midblock Bus Turnout --
Figure 4-22. Sawtooth Bus Loading Area --
Figure 4-23. Typical Application of Diagonal Back-In/Head-Out Parking --
Figure 4-24. Parking Lane Transition at Intersection --
CHAPTER 5 LOCAL ROADS AND STREETS --
Figure 5-1. Types of Cul-de-Sacs and Dead-End Streets --
Figure 5-2. Alley Turnarounds --
Figure 5-3. Actual Curb Radius and Effective Radius for Right-Turn Movements at Intersections --
Figure 5-4. Potential Road Network --
Figure 5-5. Turnout Design --
CHAPTER 6 COLLECTOR ROADS AND STREETS --
Chapter 6 has no figures --
CHAPTER 7 RURAL AND URBAN ARTERIALS --
Figure 7-1. Climbing Lane on Two-Lane Arterial in a Rural Area --
Figure 7-2. Two-Lane Arterial Cross Section with Ultimate Development to a Four-Lane Arterial --
Figure 7-3. Methods of Attaining Superelevation on Divided Arterials in Rural Areas --
Figure 7-4. Typical Medians on Divided Arterials in Rural Areas --
Figure 7-5. Cross Sectional Arrangements on Divided Arterials in Rural Areas --
Figure 7-6. Cross Sectional Arrangements on Divided Arterials with Frontage Roads --
Figure 7-7. Transition Zone Areas (31) --
Figure 7-8. Continuous Two-Way Left-Turn Lane --
Figure 7-9. Arterial Street in a Residential Area --
Figure 7-10. Divided Arterial Street with Parking Lane --
Figure 7-11. Divided Arterial Street with Two-Way Frontage Road --
Figure 7-12. Reserved Bus Lane --
CHAPTER 8 FREEWAYS --
Figure 8-1. Typical Ground-Level Freeway in a Rural Area --
Figure 8-2. Typical Rural Medians --
Figure 8-3. Typical Cross Section for Depressed Freeways --
Figure 8-4. Restricted Cross Sections for Depressed Freeways --
Figure 8-5. Cross Sections with Retaining Walls on Depressed Freeways without Ramps --
Figure 8-6. Depressed Freeway --
Figure 8-7. Typical Cross Sections for Elevated Freeways on Structures without Ramps --
Figure 8-8. Typical and Restricted Cross Sections for Elevated Freeways on Structures with Frontage Roads --
Figure 8-9. Typical and Restricted Cross Sections for Elevated Freeways on Embankment --
Figure 8-10. Viaduct Freeway --
Figure 8-11. Two-Level Viaduct Freeway --
Figure 8-12. Typical Cross Sections for Ground-Level Freeways --
Figure 8-13. Restricted Cross Sections for Ground-Level Freeways --
Figure 8-14. Profile Control-Combination-Type Freeway in Rolling Terrain --
Figure 8-15. Profile Control-Combination-Type Freeway in Level Terrain --
Figure 8-16. Cross-Section Control-Combination-Type Freeway --
Figure 8-17. Combination-Type Freeway --
Figure 8-18. Typical Cross Sections for Reverse-Flow Operation --
Figure 8-19. Typical Reverse Roadway Terminals --
Figure 8-20. Reverse-Flow Freeway --
Figure 8-21. Dual-Divided Freeway --
Figure 8-22. Typical Dual-Divided Freeway --
Figure 8-23. Bus Roadway Located between a Freeway and a Parallel Frontage Road --
Figure 8-24. Bus Stops at Freeway Level --
Figure 8-25. Bus Stops at Freeway-Level Diamond Interchange --
Figure 8-26. Bus Stops at Street Level on Diamond Interchange --
Figure 8-27. Joint Freeway-Transit Right-of-Way --
Figure 8-28. Typical Sections with Rail Transit in Freeway Median --
Figure 8-29. Example of Transit Station Layout --
Figure 8-31. Freeway with Rail Rapid Transit in the Median --
CHAPTER 9 INTERSECTIONS --
Figure 9-1. Conflict Points at Various Intersection Types --
Figure 9-2. Physical and Functional Area of an Intersection --
Figure 9-3. Elements of the Functional Area of an Intersection --
Figure 9-4. General Types of Intersections --
Figure 9-5. Three-Leg Intersections --
Figure 9-6. Channelized Three-Leg Intersections --
Figure 9-7. Unchannelized Four-Leg Intersections, Plain and Flared --
Figure 9-8. Channelized Four-Leg Intersections --
Figure 9-9. Four-Leg Intersections with Skew --
Figure 9-10. Channelized Multilane Four-Leg Intersections --
Figure 9-11. Realigning Multileg Intersections --
Figure 9-12. Typical Mini-Roundabout --
Figure 9-13. Typical Single-Lane Roundabout --
Figure 9-14. Typical Multilane Roundabout --
Figure 9-15. Realignment Variations at Intersections --
Figure 9-16. Approach Sight Triangles at Intersections --
Figure 9-17. Departure Sight Triangles for Intersections --
Figure 9-18. Sight Triangles at Skewed Intersections --
Figure 9-19. Channelized Right-Turn Lanes --
Figure 9-20. Effective Corner Radius --
Figure 9-21. Variations in Length of Crosswalk with Different Curb Radii (10) --
Figure 9-22. General Types and Shapes of Islands and Medians --
Figure 9-23. Alignment for Addition of Divisional Islands at Intersections --
Figure 9-24. Details of Corner Island Designs for Turning Roadways (Urban Area Location) --
Figure 9-25. Details of Corner Island Designs for Turning Roadways (Rural Cross Section on Approach) --
Figure 9-26. Nose Ramping at Approach End of Median or Corner Island --
Figure 9-27. Details of Divisional Island Design --
Figure 9-28. Development of Superelevation at Turning Roadway Terminals on a Tangent Roadway --
Figure 9-29. Development of Superelevation at Turning Roadway Terminals on a Curved Roadway (Same Direction of Curve) --
Figure 9-30. Development of Superelevation at Turning Roadway Terminals on a Curved Roadway (Opposite Direction of Curve) --
Figure 9-31. Development of Superelevation at Turning Roadway Terminals on a Tangent Roadway with a Deceleration Lane --
Figure 9-32. Functional Area Upstream of an Intersection Illustrating Components of Deceleration Lane Length --
Figure 9-33. Key Dimensions for Maneuvers and Physical Boundaries at Left-Turn Auxiliary Lanes --
Figure 9-34a. Examples of Taper Design for Left- and Right-Turn Auxiliary Lanes (U.S. Customary) --
Figure 9-34b. Examples of Taper Design for Left- and Right-Turn Auxiliary Lanes (Metric) --
Figure 9-35. Suggested Left-Turn Lane Warrants Based on Results from Benefit-Cost Evaluations for Intersections on Arterials in Urban Areas (16) --
Figure 9-36. Suggested Left-Turn Treatment Warrants Based on Results from Benefit-Cost Evaluations for Intersections on Two-Lane Highways in Rural Areas (16) --
Figure 9-37. Suggested Left-Turn Lane Warrants Based on Results from Benefit-Cost Evaluations for Intersections on Four-Lane Highways in Rural Areas (16) --
Figure 9-38. 14- to 18-ft [4.2- to 5.4-m] Median Width Left-Turn Design --
Figure 9-39. Median Left-Turn Design for Median Width of 16 ft [4.8 m] or More --
Figure 9-40. Examples of Left-Turn Lanes with Negative, Zero, and Positive Offset (10) --
Figure 9-41. Parallel and Tapered Offset Left-Turn Lane --
Figure 9-42. Four-Leg Intersection Providing Simultaneous Left Turns --
Figure 9-43. Above-Minimum Design of Median Openings (Typical Bullet-Nose Ends) --
Figure 9-44. Intersection with Jughandle Roadways for Indirect Left Turns Showing Vehicular Conflict Points --
Figure 9-45. Vehicular Movements at an Intersection with Jughandle Roadways --
Figure 9-46. Intersection with Loop Roadways for Indirect Left Turns --
Figure 9-47. Diagram of a Displaced Left-Turn Intersection Showing Vehicular Conflict Points --
Figure 9-48. Vehicular Movements at a Displaced Left-Turn Intersection --
Figure 9-49. Typical Arrangement of U-Turn Roadways for Indirect Left Turns on Arterials with Wide Medians --
Figure 9-50. Vehicular Movements at an Intersection with U-Turn Roadways for Indirect Left Turns --
Figure 9-51. Typical Restricted Crossing U-Turn (RCUT) Intersection --
Figure 9-52. Illustration of Pedestrian Path through a Restricted Crossing U-Turn (RCUT) Intersection (12) --
Figure 9-53. Conflict Diagram for Median U-Turn Configuration Showing Vehicular Conflict Points --
Figure 9-54. Conflict Diagram for Restricted Crossing U-Turn Configuration Showing Vehicle Conflict Points --
Figure 9-55. Bidirectional (Conventional) and Directional Median Openings --
Figure 9-56. Typical Loon Design to Facilitate U-Turning Traffic on Arterials with Restricted Median Widths (27) --
Figure 9-57. Dual U-Turn Directional Crossover Design (27) --
Figure 9-58. Special Indirect U-Turn Roadways with Narrow Medians --
Figure 9-59. Example of a Roundabout in an Urban Area --
Figure 9-60. Example of a Roundabout in a Rural Area --
Figure 9-61. Basic Geometric Elements of a Roundabout --
Figure 9-62. Roundabout Lane Configuration Example --
Figure 9-63. Path Overlap at a Multilane Roundabout --
Figure 9-64. Intersections with Frontage Roads --
Figure 9-65. Arterial with Flush or Traversable Median Turn Lanes --
Figure 9-66. Railroad-Highway Grade Crossing --
Figure 9-67. Case A: Moving Vehicle to Cross or Stop at Railroad Crossing --
Figure 9-68. Case B: Departure of Vehicle from Stopped Position to Cross Single Railroad Track --
CHAPTER 10 GRADE SEPARATIONS AND INTERCHANGES --
Figure 10-1. Interchange Configurations --
Figure 10-2. Factors Influencing Length of Access Control along an Interchange Crossroad --
Figure 10-3. Typical Grade Separation Structures with Closed Abutments --
Figure 10-4. Typical Grade Separation Structure with Open-End Span --
Figure 10-5. Multilevel Grade Separation Structures --
Figure 10-6. Lateral Offset for Major Roadway Underpasses --
Figure 10-7. Typical Overpass Structures --
Figure 10-8. Flat Terrain, Distance Needed to Achieve Grade Separation --
Figure 10-9. Three-Leg Interchanges with Single Structures --
Figure 10-10. Three-Leg Interchanges with Multiple Structures --
Figure 10-11. Three-Leg Interchange (T-Type or Trumpet) --
Figure 10-12. Three-Leg Interchange Directional Design --
Figure 10-13. Directional Three-Leg Interchange at a River Crossing --
Figure 10-14. Trumpet Freeway-to-Freeway Interchange --
Figure 10-15. Four-Leg Interchanges, Ramps in One Quadrant --
Figure 10-16. Typical Four-Leg Diamond Interchange --
Figure 10-17. Diamond Interchanges, Conventional Arrangements --
Figure 10-18. Diamond Interchange Arrangements to Reduce Traffic Conflicts --
Figure 10-19. Diamond Interchanges with Additional Structures --
Figure 10-20. Freeway with a Three-Level Diamond Interchange --
Figure 10-21. X-Pattern Ramp Arrangement --
Figure 10-22. Diamond Interchange with Roundabouts at the Crossroad Ramp Terminals --
Figure 10-23. Underpass Single-Point Diamond Interchange --
Figure 10-24. Typical SPDI Underpass Configuration in Restricted Right-of-Way --
Figure 10-25. Overpass Layout for an SPDI with a Frontage Road and a Separate U-Turn Movement --
Figure 10-26. Underpass SPDI and Overpass SPDI --
Figure 10-27. Underpass and Overpass Diverging Diamond Interchanges --
Figure 10-28. Partial Cloverleaf Interchange --
Figure 10-29. Four-Leg Interchange, Cloverleaf with Collector—Distributor Roads --
Figure 10-30. Schematic of Partial Cloverleaf Ramp Arrangements, Exit and Entrance Turns --
Figure 10-31. Four-Leg Interchange (Partial or Two-Quadrant Cloverleaf with Ramps before Main Structure) --
Figure 10-32. Four-Leg Interchange (Partial or Two-Quadrant Cloverleaf with Ramps before Main Structure) --
Figure 10-33. Directional Interchanges with Weaving Areas --
Figure 10-34. Directional Interchanges with No Weaving --
Figure 10-35. Directional Interchanges with Multilevel Structures --
Figure 10-36. Directional Interchange, Two Semidirect Connections --
Figure 10-37. Four-Level Directional Interchange --
Figure 10-38. Four-Level Directional Interchange --
Figure 10-39. Directional Interchange with Semidirect Connection and Loops --
Figure 10-40. Offset Interchange via Ramp Highway --
Figure 10-41. Four-Leg Interchange, Diamond with a Direct Connection --
Figure 10-42. Four-Leg Interchange, Cloverleaf with a Semidirect Connection --
Figure 10-43. Cloverleaf interchange with Semidirect Connection --
Figure 10-44. Complex Interchange Arrangement --
Figure 10-45. Adaptability of Interchanges on Freeways as Related to Types of Intersecting Facilities --
Figure 10-46. Widening for Divisional Island at Interchanges --
Figure 10-47. Interchange Spacing as Measured between Successive Crossroads (78) --
Figure 10-48. Arrangement of Exits between Successive Interchanges --
Figure 10-49. Interchange Forms to Maintain Route Continuity --
Figure 10-50. Collector—Distributor Road on Major—Minor Roadway Overlap --
Figure 10-51. Schematic of Basic Number of Lanes --
Figure 10-52. Typical Examples of Lane Balance --
Figure 10-53. Coordination of Lane Balance and Basic Number of Lanes --
Figure 10-54. Alternative Methods of Reducing or Dropping Auxiliary Lanes --
Figure 10-55. Coordination of Lane Balance and Basic Number of Lanes through Application of Auxiliary Lanes --
Figure 10-56. Auxiliary Lane Dropped at Two-Lane Exit --
Figure 10-57. Interchange Forms with One and Two Exits --
Figure 10-58. Two-Lane Crossroad Designs to Discourage Wrong-Way Entry --
Figure 10-59. Divided Crossroad Designs to Discourage Wrong-Way Entry --
Figure 10-60. General Types of Ramps --
Figure 10-61. Ramp Shapes --
Figure 10-62. Development of Superelevation at Free-Flow Ramp Terminals --
Figure 10-63. Typical Exit Gore Area Characteristics --
Figure 10-64. Typical Gore Details --
Figure 10-65. Traveled-Way Narrowing on Entrance Ramps --
Figure 10-66. Gore Area, Single-Lane Exit --
Figure 10-67. Gore Area, Major Fork --
Figure 10-68. Gore Area, Two-Lane Exit --
Figure 10-69. Entrance Terminal --
Figure 10-70. Recommended Minimum Ramp Terminal Spacing --
Figure 10-71. Ramp Spacing Dimension --
Figure 10-72. Typical Single-Lane Entrance Ramps --
Figure 10-73. Exit Ramps—Single Lane --
Figure 10-74a. Layout of Taper-Type Terminals on Curves (U.S. Customary) --
Figure 10-74b. Layout of Taper-Type Terminals on Curves (Metric) --
Figure 10-75. Parallel-Type Ramp Terminals on Curves --
Figure 10-76. Typical Two-Lane Entrance Ramps --
Figure 10-77. Two-Lane Exit Terminals --
Figure 10-78. Major Forks --
Figure 10-79. Branch Connections --
Figure 10-80. Diagram of Freeway Configuration with Closely Spaced Ramps but Limited Weaving.

LIST OF TABLES --
CHAPTER 2 DESIGN CONTROLS AND CRITERIA --
Table 2-1. Corresponding Design Speeds in Metric and U.S. Customary Units --
Table 2-2. General Definitions of Levels of Service --
Table 2-3. Guidelines for Selection of Design Levels of Service --
Table 2-4a. Design Vehicle Dimensions (U.S. Customary Units) --
Table 2-4b. Design Vehicle Dimensions (Metric Units) --
Table 2-5a. Minimum Turning Radii of Design Vehicles (U.S. Customary Units) --
Table 2-5b. Minimum Turning Radii of Design Vehicles (Metric Units) --
CHAPTER 3 ELEMENTS OF DESIGN --
Table 3-1. Stopping Sight Distance on Level Roadways --
Table 3-2. Stopping Sight Distance on Grades --
Table 3-3. Decision Sight Distance --
Table 3-4. Passing Sight Distance for Design of Two-Lane Highways --
Table 3-5. Minimum Passing Zone Lengths to Be included in Traffic Operational Analyses --
Table 3-6. Average Running Speeds --
Table 3-7. Minimum Radius Using Limiting Values of e and f --
Table 3-8. Minimum Radii for Design Superelevation Rates, Design Speeds, and e max= 4% --
Table 3-9. Minimum Radii for Design Superelevation Rates, Design Speeds, and e max= 6% --
Table 3-10. Minimum Radii for Design Superelevation Rates, Design Speeds, and e max= 8% --
Table 3-11. Minimum Radii for Design Superelevation Rates, Design Speeds, and e max= 10% --
Table 3-12. Minimum Radii for Design Superelevation Rates, Design Speeds, and e max= 12% --
Table 3-13. Minimum Radii and Superelevation for Low-Speed Streets in Urban Areas --
Table 3-14. Lengths of Circular Arcs for Different Compound Curve Radii --
Table 3-15. Adjustment Factor for Number of Lanes Rotated --
Table 3-16a. Superelevation Runoff Lr (ft) for Horizontal Curves --
Table 3-16b. Superelevation Runoff Lr (m) for Horizontal Curves --
Table 3-17. Limiting Superelevation Rates --
Table 3-18. Maximum Radius for Use of a Spiral Curve Transition --
Table 3-19. Desirable Length of Spiral Curve Transition --
Table 3-20. Superelevation Rates Associated with Large Relative Gradients --
Table 3-21. Tangent Runout Length for Spiral Curve Transition Design --
Table 3-22. Minimum Lengths of Spiral for Intersection Curves --
Table 3-23. Length of Circular Arc for a Compound Intersection Curve When Followed by a Curve of One-Half Radius or Preceded by a Curve of Double Radius --
Table 3-24a. Calculated and Design Values For Traveled Way Widening on Open Highway Curves (Two-Lane Highways, One-Way Or Two-Way) (U.S. Customary) --
Table 3-24b. Calculated and Design Values for Traveled Way Widening on Open Highway Curves (Two-Lane Highways, One-Way or Two-Way) (Metric) --
Table 3-25. Adjustments for Traveled Way Widening Values on Open Highway Curves (Two-Lane Highways, One-Way or Two-Way) --
Table 3-26a. Derived Pavement Widths for Turning Roadways for Different Design Vehicles (U.S. Customary) --
Table 3-26b. Derived Pavement Widths for Turning Roadways for Different Design Vehicles (Metric) --
Table 3-27. Design Widths of Pavements for Turning Roadways --
Table 3-28. Design Width Modifications for Edge Conditions of the Traveled Way for Turning Roadways --
Table 3-29. Cases and Traffic Conditions by Design --
Table 3-30. Cases and Traffic Conditions for Larger Vehicles --
Table 3-31. Range of Usable Shoulder Widths or Equivalent Lateral Clearances outside of Turning Roadways, Not on Structure --
Table 3-32. Optimal Passing Lane Lengths for Traffic Operational Efficiency (30, 31) --
Table 3-33. Recommended Lengths of Turnouts Including Taper --
Table 3-34. Rolling Resistance of Roadway Surfacing Materials --
Table 3-35. Design Controls for Crest Vertical Curves Based on Stopping Sight Distance --
Table 3-36. Design Controls for Crest Vertical Curves Based on Passing Sight Distance --
Table 3-37. Design Controls for Sag Vertical Curves --
CHAPTER 4 CROSS-SECTION ELEMENTS --
Table 4-1. Normal Traveled-Way Cross Slope --
Table 4-2. Design Guidelines and Countermeasures to Reduce Median-Related Crashes on High-Speed Roadways (36) --
Table 4-3. Noise-Abatement Criteria for Various Land Uses (27) --
Table 4-4. Driveway Width Guidelines (31) --
CHAPTER 5 LOCAL ROADS AND STREETS --
Table 5-1. Minimum Design Speeds for Local Roads in Rural Areas --
Table 5-2. Maximum Grades for Local Roads in Rural Areas --
Table 5-3. Design Controls for Stopping Sight Distance and for Crest and Sag Vertical Curves --
Table 5-4. Design Controls for Crest Vertical Curves Based on Passing Sight Distance --
Table 5-5. Minimum Width of Traveled Way and Shoulders for Two-Lane Local Roads in Rural Areas --
Table 5-6. Minimum Clear Roadway Widths and Design Loadings for New and Reconstructed Bridges --
Table 5-7. Maximum Grades for Recreational Roads --
Table 5-8. Design Controls for Stopping Sight Distance and for Crest and Sag Vertical Curves—Recreational Roads --
Table 5-9. Guidelines for Minimum Radius of Curvature for New Construction of Unpaved Surfaces with No Superelevation [adapted from (20)] --
Table 5-10. Design Controls for Passing Sight Distance for Crest Vertical Curves—Recreational Roads --
Table 5-11. Widths of Traveled Way and Shoulders—Recreational Roads --
Table 5-12. Design Speeds for Resource Recovery and Local Service Roads --
CHAPTER 6 COLLECTOR ROADS AND STREETS --
Table 6-1. Minimum Design Speeds for Collectors in the Rural Context --
Table 6-2. Maximum Grades for Collectors in Rural Areas --
Table 6-3. Design Controls for Stopping Sight Distance and for Crest and Sag Vertical Curves --
Table 6-4. Design Controls for Crest Vertical Curves Based on Passing Sight Distance --
Table 6-5. Minimum Width of Traveled Way and Shoulders --
Table 6-6. Minimum Roadway Widths and Design Loadings for New and Reconstructed Bridges --
Table 6-7. Maximum Grades for Collectors in the Urban and Urban Core Contexts --
CHAPTER 7 RURAL AND URBAN ARTERIALS --
Table 7-1. Minimum Sight Distances for Arterials in Rural Areas--
Table 7-2. Maximum Grades for Arterials in Rural Areas --
Table 7-3. Minimum Width of Traveled Way and Usable Shoulder for Arterials in Rural Areas --
Table 7-4a. Maximum Grades for Urban Arterials, U.S. Customary --
Table 7-4b. Maximum Grades for Urban Arterials, Metric --
CHAPTER 8 FREEWAYS --
Table 8-1. Maximum Grades for Freeways in Rural and Urban Areas --
CHAPTER 9 INTERSECTIONS --
Table 9-1. Key Dimensions of Specific Types of Nonmotorized Users --
Table 9-2. Motor Vehicle Level of Service Definitions for Signalized Intersections (49) --
Table 9-3. Comparison of Roundabout Types (41) --
Table 9-4. Length of Sight Triangle Leg—Case A, No Traffic Control --
Table 9-5. Adjustment Factors for Intersection Sight Distance Based on Approach Grade --
Table 9-6. Time Gap for Case B1, Left Turn from Stop --
Table 9-7. Design Intersection Sight Distance—Case B1, Left Turn from Stop --
Table 9-8. Time Gap for Case B2—Right Turn from Stop --
Table 9-9. Design Intersection Sight Distance—Case B2, Right Turn from Stop --
Table 9-10. Time Gap for Case B3, Crossing Maneuver from the Minor Road --
Table 9-11. Design Intersection Sight Distance—Case B3, Crossing Maneuver --
Table 9-12. Case C1—Crossing Maneuvers from Yield-Controlled Approaches, Length of Minor Road Leg and Travel Times --
Table 9-13. Length of Sight Triangle Leg along Major Road—Case C1, Crossing Maneuver at Yield-Controlled Intersections --
Table 9-14. Time Gap for Case C2, Left or Right Turn at Yield-Controlled Intersections --
Table 9-15. Design Intersection Sight Distance—Case C2, Left or Right Turn at Yield-55 Controlled Intersections --
Table 9-16. Time Gap for Case F, Left Turns from the Major Road --
Table 9-17. Intersection Sight Distance—Case F, Left Turn from the Major Road --
Table 9-18. Maximum Algebraic Difference in Cross Slope at Turning Roadway Terminals --
Table 9-19. Stopping Sight Distance for Turning Roadways --
Table 9-20. Desirable Lane Change and Deceleration Distances --
Table 9-21. Calculated Storage Lengths to Accommodate the 50th Percentile Critical Gap (16) --
Table 9-22. Calculated Storage Lengths to Accommodate the 85th Percentile Critical Gap (16) --
Table 9-23. Queue Storage Length Adjustments for Trucks (4 8) --
Table 9-24. Suggested Left-Turn Lane Guidelines Based on Results from Benefit–Cost Evaluations for Unsignalized Intersections on Arterials in Urban Areas (16) --
Table 9-25. Suggested Left-Turn Treatment Guidelines Based on Results from Benefit–Cost Evaluations for Intersections on Two-Lane Highways in Rural Areas (16) --
Table 9-26. Suggested Left-Turn Lane Guidelines Based on Results from Benefit—Cost Evaluations for Unsignalized Intersections on Four-Lane Highways in Rural Areas (16) --
Table 9-27. Swept Path Widths for 90-Degree Left Turns (23) --
Table 9-28. Minimum Designs for U-Turns --
Table 9-29. Design Sight Distance for Combination of Motor Vehicle and Train Speeds; 73.5-ft 122 4-mi Truck Crossing a Single Set of Tracks at 90 Degrees --
CHAPTER 10 GRADE SEPARATIONS AND INTERCHANGES --
Table 10-1. Guide Values for Ramp Design Speed as Related to Highway Design Speed --
Table 10-2. Guidelines for Maximum Ramp Grade --
Table 10-3. Minimum Length of Taper beyond an Offset Nose --
Table 10-4. Minimum Acceleration Lane Lengths for Entrance Terminals with Flat Grades of Less Than 3 Percent --
Table 10-5. Speed Change Lane Adjustment Factors as a Function of Grade --
Table 10-6. Minimum Deceleration Lane Lengths for Exit Terminals with Flat Grades of Less Than 3 Percent.

Highway engineers, as designers, strive to meet the needs of highway users while maintaining the integrity of the environment. Unique combinations of design controls and constraints that are often conflicting call for unique design solutions. A Policy on Geometric Design of Highways and Streets provides guidance based on established practices that are supplemented by recent research. This document is also intended as a comprehensive reference manual to assist in administrative, planning, and educational efforts pertaining to design formulation.