Traffic Engineering deals with the planning, design and implementation of traffic flow, and road infrastructure and facilities. This book provides in-depth information about road user characteristics and highway geometric design. It explains the collection and analysis of different types of traffic data, obtained as part of various studies. It also describes the design of different types of intersections and illustrates the use of road markings and lighting. Recent advances such as Intelligent Transportation System are also explored. This book will be useful to undergraduate and postgraduate students as well as to researchers and practicing engineers.

R Srinivasa Kumar is a faculty member of the Department of Civil Engineering, University College of Engineering, Osmania University, Hyderabad. He was awarded the Indian Roads Congress Commendation Certificate for the best research paper published in the IRC Journal (2001–02). He has also authored textbooks on highway engineering, pavement design and maintenance, and transportation engineering.

Preface
Acknowledgements
1. Introduction to Road Traffic Engineering
1.0 Introduction
1.1 Traffic Problems
1.2 Reasons for Collecting Data
1.3 Types of Studies
1.3.1 Frequency of Traffic Data Collection
Multiple Choice Questions
Questions
2. Road User and Vehicle Characteristics
2.0 Introduction
2.1 Road User
2.1.1 Road User Characteristics
2.1.2 Reaction Process
2.1.3 Rate of Change of the Visual Angle
2.2 Vehicle
2.2.1 Vehicle Characteristics
2.3 Road Characteristics
2.3.1 Surface Characteristics
2.3.2 Lighting
2.4 Traffic Control Devices
2.5 The General Environment
Multiple Choice Questions
Questions
3. Highway Geometric Design
3.0 Introduction
3.1 Vehicle Dimensions
3.2 Terrain Classification
3.3 Design Speed
3.4 Cross-Sectional Elements
3.4.1 Boundary Lines
3.4.2 Right of Way or Road–Land Width
3.4.3 Carriageway Width and Road Width
3.4.4 Shoulder
3.4.5 Camber
3.5 Sight Distance
3.5.1 Safe Stopping Sight Distance (SSD)
3.5.2 Overtaking Sight Distance (OSD) or Passing Sight Distance (PSD)
3.5.3 Intermediate Sight Distance (ISD)
3.5.4 Intersection Sight Distance (ISSD)
3.5.5 Sight Distance at Medians
3.6 Superelevation
3.6.1 Design of Superelevation
3.6.2 Design Rate of Superelevation
3.6.3 Design Side Friction Factor
3.6.4 Analysis of Curve Radii
3.6.5 Attaining Superelevation
3.6.6 Rate of Change of Superelevation
3.7 Widening of Carriageway on Curves
3.8 Horizontal Curves
3.8.1 Sight Distance on Horizontal Curves
3.8.2 Transition Curve
3.8.3 Length of Transition Curve
3.8.4 Elements of the Transition Curve
3.9 Longitudinal Gradient
3.10 Compensation of Grade on Horizontal Curves
3.11 Vertical Curves
3.11.1 Types of Vertical Curves
3.11.2 Length of Vertical Curves
3.11.3 Sight Distance on Sag Curves Passing Under an Overhead Structure
3.12 Bus Bay
3.13 Road Humps and Bumps
3.14 Geometric Design of Bike Paths
3.15 Consistency in Highway Geometric Design
Multiple Choice Questions
Questions
4. Traffic Volume Studies
4.0 Introduction
4.1 Objectives of Traffic Volume Studies
4.2 Types of Traffic Counts
4.2.1 Vehicular Traffic Volume (or Flow) Survey
4.2.2 Pedestrian Traffic Volume Survey
4.3 Introduction to Pedestrian Volume Studies
4.4 Objectives of Pedestrian Volume Studies
4.5 Use Criteria for Pedestrian Volume Studies
4.6 Terminology
4.7 Types of Pedestrian Transport Networks
4.8 Factors Affecting Pedestrian Demand
4.9 Pedestrian Data Collection Methods
4.9.1 Manual Counting Techniques
4.9.2 Automatic Counting Techniques
4.10 Location of Counting Stations
4.11 Pedestrian Volume Characteristics
4.12 Design Volume
4.13 Presentation of Pedestrian Volume Data
4.14 Pedestrian Flow Characteristics
4.14.1 Pedestrian Walking Speed
4.14.2 Pedestrian Walking Space
4.14.3 Pedestrian Start-Up Time
4.14.4 Pedestrian Capacity
4.14.5 Pedestrian Speed–Density (V–K) Relationship
4.14.6 Pedestrian Flow–Density Relationship
4.14.7 Travel Time–Speed–Flow Rate Relationship
4.14.8 Pedestrian Speed–Flow Relationship
4.14.9 Pedestrian Speed–Space Relationship
4.14.10 Pedestrian Flow–Space Relationship
4.15 Level of Service (LOS)
4.15.1 LOS Criteria for Uninterrupted Flow Pedestrian Facility
4.15.2 LOS Criteria for Stairways and Queuing
4.15.3 LOS Criteria for Interrupted Flow Pedestrian Facility
4.16 Time–Space (TS) Analysis Method
4.17 Design Guidelines
4.18 Solved Problems
Multiple Choice Questions
Questions
5. Traffic Count Techniques and Analysis of Traffic Volume Data
5.0 Types of Traffic Counting Methods
5.1 Manual Traffic Count
5.2 Automatic Traffic Count (ATC)
5.2.1 Intrusive Sensors
5.2.2 Non-Intrusive Sensors
5.3 Factors Affecting the Selection of Technology
5.4 Duration of Traffic Count
5.5 Traffic Attributes
5.6 Presentation of Traffic Volume Data
5.6.1 Variations in Traffic Flow
5.6.2 Summary Tables
5.6.3 Graphic Summary of Flow at Intersections
5.7 Analysis of Traffic Volume Data – Basic Terminology
5.8 Traffic Volume Data Products
5.8.1 Monthly Average Days of the Week Traffic (MADWT)
5.8.2 Monthly Average Daily Traffic (MADT)
5.8.3 Monthly Average Weekday Daily Traffic (MAWDT)
5.8.4 Monthly Average Weekend Daily Traffic (MAWET)
5.8.5 Average Annual Weekday Traffic (AAWT)
5.8.6 Average Weekday Traffic (AWT)
5.8.7 Annual Average Daily Truck Traffic (AADTT)
5.8.8 Annual Average Weekday Traffic (AAWDT)
5.8.9 Annual Average Day of Week Traffic (AADWT)
5.8.10 Average Annual Daily Traffic (AADT)
5.8.11 Annual Average Weekend Traffic (AAWET)
5.8.12 Annual Vehicle Distance Travelled (AVDT)
5.8.13 Vehicle Miles Travelled (VMT)
5.8.14 Average Daily Traffic (ADT)
5.8.15 Axle Correction Factor (ACF)
5.8.16 Seasonal Correction Factor (SCF) or Seasonal Adjustment Factor (SAF)
5.8.17 Seasonal Average Daily Traffic (SADT)
5.8.18 Average Summer Daily Traffic (ASDT)
5.8.19 Seasonal Average Daily Traffic Adjustment Factors (SADTAF)
5.8.20 Peak Hour Factor (PFH)
5.8.21 Design Hour (DH)
5.8.22 Design Year (DV)
5.8.23 Design Hour Volume (DHV)
5.8.24 K-Factor or Design Hour Factor
5.8.25 Design Hour Truck (DHT)
5.8.26 Design Hour Factor
5.8.27 Directional Distribution (D) or Directional Split of Traffic
5.8.28 Directional Design Hour Volume (DDHV)
5.9 Solved Problems
Multiple Choice Questions
Questions
6. Spot Speed Studies and Characteristics
6.0 Introduction to Speed Studies
6.1 Spot Speed Study
6.1.1 Factors Affecting Spot Speed
6.1.2 Applications of Spot Speed Data
6.2 Other Definitions of Speed
6.2.1 Sample Size
6.3 Solved Problems
Multiple Choice Questions
Questions
7. Origin and Destination Studies
7.0 Introduction
7.1 OD Data
7.2 The OD Study Area
7.3 OD Data Collection Methods
7.3.1 Registration Questionnaire Survey
7.3.2 Mail-Back Questionnaire or Self-Completion Postcard Survey
(or Roadside Handout Survey)
7.3.3 Roadside Interview Survey
7.3.4 Home Interview Survey
7.3.5 Tag-on-Car Survey
7.3.6 Carousel Method
7.3.7 Licence Plate Survey
7.3.8 Comments and Remarks
7.3.9 Other Methods Relating to ITS
7.4 Selecting a Method
7.5 Sample Size
7.6 Uses of OD Data
7.7 Presentation of OD Data
7.8 Solved Problem
Multiple Choice Questions
Questions
8. Travel Time and Delay Studies
8.0 Introduction
8.1 Factors Affecting Speed and Delay
8.2 Methods of Measurement of Travel Time and Delays on any Selected Length of a Route
8.2.1 Floating Car Method (Moving Observer Method)
8.2.2 Test Car Procedure
8.2.3 Licence Plate Matching Method
8.2.4 Fixed Time Interval Photographs
8.2.5 Elevated Observer Method
8.2.6 Field Interviews (Survey)
8.2.7 GIS and GPS Method
8.2.8 Bluetooth Technologies
8.3 Sample Size
8.4 Presentation of Travel Time and Delay Data
8.4.1 Tabular Form
8.4.2 Time Contour Map
8.4.3 Time Bar Chart
8.4.4 Speed Profiles
8.4.5 Frequency Distribution Curve
8.5 Solved Problems
Multiple Choice Questions
Questions
9. Intersection Delay Studies
9.0 Introduction
9.1 Types of Delays at Intersections
9.2 Methods of Measuring Delay Through Intersections
9.2.1 Stopped Vehicle Method
9.2.2 Elevated Observer Method
9.2.3 Sample Size
9.3 Speed and Delay Formulae
9.4 Solved Problems
Multiple Choice Questions
Questions
10. Traffic Flow Characteristics
10.0 Introduction
10.1 Traffic Stream Parameters
10.1.1 Space Headway and Time Headway
10.1.2 Lane Occupancy
10.1.3 Density
10.1.4 Lane Capacity
10.2 Fundamental Relationships Between Traffic Flow Parameters
10.2.1 Speed–Density (V–K) Relationship
10.2.2 Speed–Flow (V–Q) Relationship
10.2.3 Flow–Density (Q–K) Relationship
10.2.4 Density–Spacing (K–Ss) Relationship
10.3 Macroscopic Traffic Stream Models
10.3.1 Greenshield’s Linear Model
10.3.2 Greenberg’s Logarithmic Model
10.3.3 Underwood’s Exponential Model
10.3.4 Multi-Regime Models
10.4 Microscopic Traffic Stream Models
10.4.1 The Car-Following Theory
10.4.2 GM Model
10.5 Shock Waves in Traffic Streams
10.5.1 Shock Wave Speed
10.6 Level of Service
10.7 Equivalency Factors
10.7.1 Factors Affecting Equivalency Factors (PCU Values)
10.8 Design Service Volume
10.9 Solved Problems
Multiple Choice Questions
Questions 294
11. Introduction to Intersections and Design Guidelines for At-Grade Intersections
11.0 Introduction
11.1 Access Management
11.2 Classification of Intersections
11.3 Classification of At-Grade Intersections
11.4 Low-Cost Traffic Management Techniques
11.5 Factors Considered in the Design of Intersections
11.6 Design Principles of At-Grade Intersections
11.6.1 Design Vehicle
11.6.2 Stopping Sight Distance
11.6.3 Sight Distance Triangles at an Intersection
11.6.4 Types of Sight Triangles at an Intersection
11.6.5 Sight Distance at Median
11.7 Principles of Channelisation
11.8 Elements of Channelisation
11.8.1 Alignment of Lanes
11.8.2 Islands
11.8.3 Kerbs
11.8.4 Directional Islands
11.8.5 Median Islands
11.8.6 Median End Treatment
11.8.7 Spacing of Median Opening or Median Break Spacing
11.8.8 Dividers
11.8.9 Splitter Islands
11.8.10 Tapers and Transitions
11.8.11 Auxiliary Lanes
11.9 Retrofit Actions
11.9.1 Retrofit Techniques
11.9.2 Specific Guidelines on Corrections to Skewed Intersections
Multiple Choice Questions
Questions
12. Design and Analysis of Rotary Intersections
12.0 The Concept of Traffic Rotary Operations
12.1 Advantages of Traffic Rotaries
12.2 Disadvantages of Traffic Rotaries
12.3 Suitability of Traffic Rotaries/Roundabouts
12.4 Design Criteria and Guidelines
12.4.1 Geometric Standards
12.4.2 Operating Standards
12.5 Data Collection and Analysis
12.5.1 Methods of Data Collection
12.5.2 Operational Performance Evaluation
12.5.3 Capacity Analysis
12.6 Solved Problems
Multiple Choice Questions
Questions
13. Design of Signalised Intersections
13.0 Introduction
13.1 Advantages of Signal Control
13.2 Disadvantages of Signal Control
13.3 Warrants for Traffic Signal Installation
13.4 Traffic Signal Design Elements
13.5 Data Collection
13.6 Traffic Control Signal Lights
13.7 Commonly Used Terminology
13.8 Types of Traffic Signal Controls
13.9 Concepts of Traffic Signal Time Design
13.9.1 Phasing
13.9.2 Saturation Flow Rate
13.9.3 Estimation of Saturation Flow
13.9.4 Lost Time
13.9.5 Cycle Time By Webster’s Method
13.9.6 Effective Green Time
13.9.7 Green Time
13.10 Signal Performance Measurement
13.10.1 Capacity of an Intersection
13.10.2 Degree of Saturation
13.10.3 Level of Service (LOS)
13.10.4 Other Parameters
13.11 Design of Isolated Fixed Time Signal
13.11.1 IRC: 93 Method
13.11.2 Guiding Standards
13.12 Introduction to Coordinated Signal Control Systems
13.12.1 Need for Coordinated Control
13.12.2 Basic Concepts of Signal Coordination
13.12.3 Factors Affecting Coordination
13.13 Types of Coordinated Traffic Signal Control Systems
13.13.1 Simultaneous Signal Control System
13.13.2 Alternate Signal Control System
13.13.3 Simple Progressive Signal Control System
13.13.4 Flexible Progressive Signal Control System
13.14 Review of Signal Timing
13.15 Solved Problems
Multiple Choice Questions
Questions
14. Basics of Queuing Theory and Delay Analysis
14.0 Introduction to Queuing Theory
14.1 Queuing System
14.1.1 Queuing System Classification
14.1.2 Little’s Theorem
14.1.3 Queuing Models
14.2 Analysis of Delay and Queuing at Signalised Intersections
14.2.1 Methods of Delay Analysis at Isolated Signalised Intersections
Multiple Choice Questions
Questions
15. Design Guidelines for Grade-Separated Intersections and Interchanges
15.0 Introduction
15.1 Grade-Separated Structures
15.2 Factors Affecting the Selection of an Interchange
15.3 Classification of Grade-Separated Structures
15.3.1 Overpass or Bridge
15.3.2 Underpass
15.4 Classification of Ramps
15.4.1 Classification of Ramps Based on Direction of Use
15.4.2 Classification of Ramps Based on Access Control
15.5 Interchange Design Principles
15.5.1 Cardinal Principles of Interchange Design
15.5.2 Secondary Principles of Interchange Design
15.6 Classification of Interchanges
15.6.1 Classification Based on the Number of Approach Legs
15.6.2 Classification Based on Directional Use
15.6.3 Classification Based on Access Control
15.7 Interchange Configurations
15.7.1 Three-Leg Interchanges
15.7.2 Diamond Interchanges
15.7.3 Single Point Urban Interchange (SPUI)
15.7.4 Diverging Diamond Interchange (DDI)
15.7.5 Double Crossover Merging Interchange (DCMI)
15.7.6 Three-Level Diamond Interchange
15.7.7 Variants of Diamond Interchanges
15.7.8 Multi-Level Stack Interchanges
15.7.9 Cloverleaf Interchanges
15.7.10 Parclo (Partial Cloverleaf Interchange)
15.7.11 Turbine Interchange
15.8 Guidelines for the Design of Interchange Components
15.8.1 Lane Balance
15.8.2 Weaving Section
15.8.3 Ramp Design
15.8.4 Ramp Spacing
15.8.5 Entrance Ramp Taper Design
15.8.6 Exit Ramp Taper Design
15.8.7 Gores
15.8.8 Sight Distance
15.8.9 Other Considerations
15.8.10 Access Control
15.8.11 Comparative and Evaluation Studies
Multiple Choice Questions
Questions
16. Parking Studies
16.0 Introduction
16.1 Basic Terminology
16.2 Classification of Parking Facilities
16.2.1 On-Street/ Kerb/Roadside Parking
16.2.2 Off-Street Parking
16.3 Steps in Parking Studies
16.4 Parking Surveys
16.4.1 In–Out Survey
16.4.2 Fixed Period Sampling
16.4.3 Licence Plate Method of Survey
16.5 Characteristics of Parking Facilities
16.6 Analysis of Parking Data
16.7 Parking Management Strategies
Multiple Choice Questions
Questions
17. Road Markings
17.0 Introduction
17.1 Classification of Road Markings
17.2 Line Markings
17.2.1 Centre Line
17.2.2 Transverse Markings
17.2.3 Hazard Markings
17.2.4 Block Markings
17.2.5 Arrow Markings
17.2.6 Directional Markings
17.2.7 Facility Markings
17.2.8 Object Markings
17.2.9 Colour Pavement Markings
17.3 Road Studs
17.4 Preview Distance Requirements
17.5 Phenomenon of Diffusion, Reflection, Refraction and Retroreflectivity
17.5.1 Measurement of Retroreflectivity
17.5.2 Instruments Used to Measure Retroreflectivity
17.6 Materials Used for Road Markings
17.7 Performance Assessment of Road Markings
17.8 Anti-Skid Tests on Road Markings
Multiple Choice Questions
Questions
18. Road Traffic Signs
18.0 Introduction
18.1 Classification of Signs
18.2 Basic Elements of Road Signs
18.2.1 Shape
18.2.2 Colour
18.2.3 Lettering   
18.2.4 Symbols
18.3 Functional Aspects of Road Signs
18.3.1 Regulatory or Mandatory Signs
18.3.2 Warning, Cautionary or Precautionary Signs
18.3.3 Information/Guide Signs
18.3.4 Variable Message Signs
18.3.5 Object/Curve/Hazard Markers, Bollards and Junction Definition Posts
18.3.6 Miscellaneous Devices/Signs
18.4 Sign Legibility Distance
18.4.1 Australian Practice
18.4.2 Indian Practice
18.4.3 USSC Recommended Practice of Thumb Rule
18.5 Lateral Clearance and Location of Signs
18.5.1 Lateral Placement and Height
18.5.2 Longitudinal Placement
18.5.3 Sign Orientation
18.5.4 Sign Support Standards
18.5.5 Warrants
18.6 Illumination and Retroflection
18.7 Materials Used for Signs
18.8 The Cone of Retroreflection
18.9 Measurement of Retroreflectivity of Signs
Multiple Choice Questions
Questions
19. Roadway Lighting
19.0 Introduction
19.1 Factors Affecting Night-Time Visibility
19.2 Objectives of Roadway Lighting
19.3 Glossary of Terms
19.4 Lighting Laws
19.4.1 Inverse Square Law
19.4.2 Cosine Law
19.5 Types of Lamps
19.6 Lighting Requirements
19.7 Warrants for Lighting
19.8 Factors Affecting the Selection of Appropriate Lighting System
19.9 Lighting Correction Factors
19.10 Design Elements of Lighting System
19.10.1 Lateral Luminaire Light Distribution
19.10.2 Vertical Light Distribution
19.10.3 Luminaire Cut-Off Classification
19.10.4 Types of Poles
19.10.5 Pole Height
19.10.6 Pole Arms
19.10.7 Mounting Height and Type of Luminaire
19.10.8 Luminaire Arrangements
19.10.9 Lighting Level Requirements
19.10.10 Methods of Spacing of Lighting Units
19.10.11 Lateral Placement of Poles (Luminaire)
19.11 Design of Roadway/Street Lighting System
19.12 Methods of Pole Installation
19.13 Smart/Intelligent Street Lighting System
19.13.1 Components of ISL
19.14 Life Cycle Cost Evaluation
Multiple Choice Questions
Questions
20. Road Traffic Accident Studies and Reconstruction
20.0 Introduction
20.1 Objectives
20.2 Basic Report Information
20.2.1 Accident Location
20.3 Assessment of Accident Data
20.4 Collision Diagrams
20.5 Condition Diagrams
20.6 Measurement Systems
20.7 Fundamental Physics Formulae Used for Reconstruction of an Accident
20.8 Accident Reconstruction Formulae
20.8.1 Determination/Measurement of Drag Factor of a Road Surface
20.8.2 Determination of the Radius of a Simple Circular Road Curve
20.8.3 Determination of Critical Speed on Superelevated Road Curves
20.8.4 Determination of Minimum Speed of the Vehicle Before Sliding (From Straight Line Skid Marks)
20.8.5 Determination of Minimum Speed of Vehicle From Yaw Mark
20.8.6 Determination of Acceleration Factor of a Vehicle From Known Distance or Travel Time
20.8.7 Combined Speed of a Vehicle Skidding on Road Surface
20.8.8 Speed of a Vehicle Falling From a Downgrade/Upgrade
20.8.9 Determination of Velocities of Vehicles at Impact/Collision
20.8.10 Determination of Velocities of Vehicles Before Impact Using Vector Diagram Graphical Method
Multiple Choice Questions
Questions
21. Analysis of Accident Data and Road Safety
21.0 Analysis of Accident Data
21.1 Road Safety Vision
21.2 Road Safety Programmes
21.3 Road Safety Measures
21.4 Evaluation of Effectiveness of Road Safety Implementation
21.4.1 Chi-Square Test to Find Goodness of Fit
21.4.2 Chi-Square Test to Determine Association Between Two Variables
21.4.3 Chi-Square Test to Determine Effectiveness of Before and After Improvements From One Group of Data
21.4.4 Standard Normal Probability Method
21.4.5 Spearman Rank–Order Correlation Coefficient
Multiple Choice Questions
Questions
22. Intelligent Transportation System
22.0 Introduction
22.1 Historical Development of ITS
22.2 Objectives of ITS
22.3 Benefits of Intelligent Transportation System
22.4 ITS Design
22.5 Technologies Used in ITS
22.5.1 Geographic Positioning System
22.5.2 Communication Technologies
22.5.3 Geographical Information System (GIS)
22.5.4 Artificial Vision System
22.5.5 Digital Mapping
22.5.6 Data Acquisition and Exchange System
22.6 ITS Architecture
22.7 V-Development Model for ITS Projects
22.8 Subsystems of ITS
22.8.1 Vehicle Detection Station (VDS)
22.8.2 Variable Message Signs (VMSS)
22.8.3 Changeable Message Signs (CMS) Systems
22.8.4 Variable Speed Limit Sign (VSLS)/Lane Control Sign (LCS)
22.8.5 Speed Enforcement System or High-Speed Driving Deterrence System
22.8.6 Red Light Violation Detection System
22.8.7 Oncoming Traffic Indication/Warning System
22.8.8 Centre Line Shifting System
22.8.9 Vehicle Information and Communication (VIC) System
22.8.10 Automatic Incident Detection (AID) and Information Provision Systems
22.8.11 Road Weather Monitoring Systems
22.8.12 Over Height Vehicle Detection System
22.8.13 Automatic Number Plate Recognition (ANPR) System or Automatic Vehicle Licence Plate Recognition
System
22.8.14 Electronic Toll Collection (ETC) System
22.8.15 Weigh-in-Motion (WIM) Systems
22.8.16 Traveller Information System (TIS)/Traveller Advisory Radio (TAR)
22.8.17 Parking Management and Guidance Systems
22.8.18 Tunnel Systems
22.8.19 Road Condition Information Signs (RCIS) Systems
22.8.20 Ramp Metering Systems (RMS)
22.8.21 Work Zone System
22.8.22 Other Systems
Multiple Choice Questions
Questions

References
Appendix
Index