Contents Chapter 1 Introduction to Highway Engineering and Traffic Analysis 1 1.1 Introduction 1 1.2 Highways and the Economy 1 1.2.1 The Highway Economy 2 1.2.2 Supply Chains 2 1.2.3 Economic Development 2 1.3 Highways, Energy and the Environment 3 1.4 Highways and the Transportation System 3 1.5 Highway Transportation and the Human Element 3 1.5.1 Passenger Transportation Modes and Traffic Congestion4 1.5.2 Highway Safety 4 1.5.3 Demographic Trends 5 1.6 Highways and Evolving Technologies 6 1.6.1 Infrastructure Technologies 6 1.6.2 Vehicle Technologies7 1.6.3 Traffic Control Technologies 7 1.7 Scope of Study8 Chapter 2 Road Vehicle Performance 9 2.1 Introduction 9 2.2 Tractive Effort and Resistance 9 2.3 Aerodynamic Resistance 10 2.4 Rolling Resistance 13 2.5 Grade Resistance 15 2.6 Available Tractive Effort 17 2.6.1 Maximum Tractive Effort 17 2.6.2 Engine-Generated Tractive Effort 19 2.7 Vehicle Acceleration22 2.8 Fuel Efficiency 26 2.9 Principles of Braking 26 2.9.1 Braking Forces 26 2.9.2 Braking Force Ratio and Efficiency 28 2.9.3 Antilock Braking Systems 32 2.9.4 Theoretical Stopping Distance 32 2.9.5 Practical Stopping Distance 35 2.9.6 Distance Traveled During Driver Perception/Reaction 38 Chapter 3 Geometric Design of Highways 45 3.1 Introduction 45 3.2 Principles of Highway Alignment 46 3.3 Vertical Alignment 47 3.3.1 Vertical Curve Fundamentals 48 3.3.2 Stopping Sight Distance 56 3.3.3 Stopping Sight Distance and Crest Vertical Curve Design 57 3.3.4 Stopping Sight Distance and Sag Vertical Curve Design 62 3.3.5 Passing Sight Distance and Crest Vertical Curve Design 68 3.3.6 Underpass Sight Distance and Sag Vertical Curve Design 70 3.4 Horizontal Alignment 73 3.4.1 Vehicle Cornering 73 3.4.2 Horizontal Curve Fundamentals 78 3.4.3 Stopping Sight Distance and Horizontal Curve Design 80 3.5 Combined Vertical and Horizontal Alignment 82 Chapter 4 Pavement Design 93 4.1 Introduction 93 4.2 Pavement Types 93 4.2.1 Flexible Pavements 94 4.2.2 Rigid Pavements 95 4.3 Pavement System Design: Principles for Flexible Pavements 95 4.3.1 Calculation of Flexible Pavement Stresses and Deflections 96 4.4 The AASHTO Flexible-Pavement Design Procedure 104 4.4.1 Serviceability Concept 105 4.4.2 Flexible-Pavement Design Equation 105 4.4.3 Structural Number 113 4.5 Pavement System Design: Principles for Rigid Pavements 117 4.5.1 Calculation of Rigid-Pavement Stresses and Deflections 117 4.6 The AASHTO Rigid-Pavement Design Procedure 120 4.7 Measuring Pavement Quality and Performance 131 4.7.1 International Roughness Index 131 4.7.2 Friction Measurements 132 4.7.3 Rut Depth 133 Chapter 5Fundamentals of Traffic Flow and Queuing Theory 139 5.1 Introduction 139 5.2 Traffic Stream Parameters 139 5.2.1 Traffic Flow, Speed, and Density 140 5.3 Basic Traffic Stream Models 145 5.3.1 Speed-Density Model 145 5.3.2 Flow-Density Model 147 5.3.3 Speed-Flow Model 148 5.4 Models Of Traffic Flow 150 5.4.1 Poisson Model 150 5.4.2 Limitations of the Poisson Model 155 5.5 Queuing Theory and Traffic Flow Analysis 155 5.5.1 Dimensions of Queuing Models 156 5.5.2 D/D/1 Queuing 156 5.5.3 M/D/1 Queuing 160 5.5.4 M/M/1 Queuing 162 5.5.5 M/M/N Queuing 163 5.6 Traffic Analysis at Highway Bottlenecks 167 Chapter 6Highway Capacity and Level-of-Service Analysis 175 6.1 Introduction 175 6.2 Level-of-Service Concept 176 6.3 Level-of-Service Determination 179 6.3.1 Base Conditions and Capacity 179 63.2 Determine Free-Flow Speed 179 6.3.3 Determine Analysis Flow Rate 180 6.3.4 Calculate Service Measure(s) and Determine LOS 180 6.4 Basic Freeway Segments 180 6.4.1 Base Conditions and Capacity 181 6.4.2 Service Measure 181 6.4.3 Determining Free-Flow Speed 185 6.4.4 Determining Analysis Flow Rate 188 6.4.5 Calculating Density and Determining LOS 193 6.5 Multilane Highways 196 6.5.1 Base Conditions and Capacity 200 6.5.2 Service Measure 200 6.5.3 Determining Free-Flow Speed 200 6.5.4 Determining Analysis Flow Rate 203 6.5.5 Calculating Density and Determining LOS 203 6.6 Two-Lane Highways 206 6.6.1 Base Conditions and Capacity 206 6.6.2 Service Measures 207 6.6.3 Determining Free-Flow Speed 208 6.6.4 Determining Analysis Flow Rate 209 6.6.5 Calculate Service Measures 211 6.6.6 Determine LOS 214 6.7 Design Traffic Volumes 217 Chapter 7 Traffic Control and Analysis at Signalized Intersections 227 7.1 Introduction 227 7.2 Intersection and Signal Control Characteristics 228 7.2.1 Actuated Control 231 7.2.2 Vehicle Detection 232 7.2.3 Typical Phase Operation 232 7.2.4 Signal Controller Operation 234 7.3 Analysis of Traffic at Signalized Intersections 236 7.3.1 Concepts and Definitions 236 7.3.2 Signalized Intersection Analysis with D/D/1 Queuing 239 7.3.3 Signalized Intersection Analysis for Level of Service 245 7.4 Optimal Traffic Signal Timing 250 7.5 Development of a Traffic Signal Phasing and Timing Plan252 7.5.1 Select Signal Phasing 252 7.5.2 Establish Analysis Lane Groups 256 7.5.3 Calculate Analysis Flow Rates and Adjusted Saturation Flow Rates 258 7.5.4 Determine Critical Lane Groups and Total Cycle Lost Time 258 7.5.5 Calculate Cycle Length 261 7.5.6 Allocate Green Time 263 7.5.7 Calculate Change and Clearance Intervals 265 7.5.8 Check Pedestrian Crossing Time 267 7.6 Level-of-Service Determination 268 7.7 Signal Coordination 273 7.7.1 Fundamental Relationships 274 7.7.2 Effective Green to Cycle Length Ratio (g/C) 277 7.7.3 Platoon Dispersion277 7.7.4 State of the Practice279 7 .7 .5 Progression Quality and Level of Service Analysis279 7.8 The Progression Adjustment Factor and Arrival Type280 Chapter 8Travel Demand and Traffic Forecasting289 8.1 Introduction289 8.2 Traveler Decisions290 8 .3 Scope of the Travel Demand and Traffic Forecasting Problem291 8.4 Trip Generation293 8.4.1 Typical Trip Generation Models 295 8.4.2 Trip Generation with Count Data Models298 8.5 Mode and Destination Choice 300 8.5.1 Methodological Approach300 8.5.2 Logit Model Applications301 8.6 Highway Route Choice307 8.6.1 Highway Performance Functions307 8.6.2 User Equilibrium308 8.6.3 Mathematical Programming Approach to User Equilibrium313 8.6.4 System Optimization315 8.7 Traffic Forecasting in Practice 319 8.8 The Traditional Four-Step Process322 8.9 The Current State of Travel Demand and Traffic Forecasting323 Appendix 8A Least Squares Estimation324 Appendix 8B Maximum-Likelihood Estimation326 Appendix AMetric Example Problems335 Appendix BMetric End-of-Chapter Problems381 Index393