Traffic Monitoring Guide

TRAFFIC MONITORING GUIDE EXECUTIVE SUMMARY

ES.1 BACKGROUND

This edition of the Traffic Monitoring Guide (TMG) is intended to provide the most up-to-date guidance to State

highway agencies about the policies, standards, procedures, reporting, and equipment utilized in a traffic monitoring program. The TMG presents recommendations that help improve and advance current programs with a view toward the future of traffic monitoring and with consideration for transportation regulations resulting from the Fixing America's Surface Transportation (FAST) Act and its predecessors.

The needs for traffic monitoring data at both the Federal, State, and local levels require that agencies have a well-designed traffic monitoring program. Traffic data are needed to assess current and past system performance and to predict future performance. Improved traffic data, including data on ramps, are needed for reporting in the Highway Performance Monitoring System (HPMS), and there are now opportunities to use traffic data acquired from Intelligent Transportation Systems (ITS) to support coordination of planning and operations functions at the various agency levels.

Continued improvements in traffic data collection technology have allowed States to improve their data collection processes and to streamline quality assurance and quality control (QA/QC) procedures. New technology also enables States to collect data on micromobility traffic, including bicycle and pedestrian traffic. The use of micromobility traffic data supports analyses regarding the impacts to the transportation network (on volumes and safety) resulting from the use of bicycles and other micromobility devices as alternative travel methods. The new technologies and procedures for traffic monitoring presented in the TMG are supplemented with practical examples from State experiences to improve traffic monitoring programs.

The TMG is written to assist both experienced traffic data collection personnel and those who are less experienced or new to traffic data collection. Reference material that will benefit traffic data collection programs is found in the Appendices.

This edition of the TMG also includes data formats for reporting traffic data, including the Individual Vehicle Record (IVR) format for reporting volume, vehicle speed, vehicle classification, and vehicle weight data. Data formats are also provided for reporting micromobility data for those agencies with capabilities to collect this type of data. This edition of the TMG has been developed with considerable input from State traffic data program managers. This approach has resulted in a practical guidance document that FHWA anticipates will be helpful to States in improving their business processes, technology, and equipment used to successfully manage their traffic monitoring programs.

ES.2 SCOPE

The scope of State traffic monitoring programs encompasses volume, classification, speed, and weight data. Traffic monitoring data from the States continues to be required to meet the reporting requirements of the Federal Highway Administration (FHWA) under 23 CFR 420.105(b), which requires States to provide data that support FHWA's reporting responsibilities to Congress and to the public. Traffic data reported under this Federal regulation are submitted as part of the annual HPMS report from each State.

ES.3 USERS

Traffic datasets are typically used to support highway agency activities that include planning, design, maintenance, operations, safety, environmental analysis, finance, engineering economics, and performance management. Each State has its own traffic data collection needs, priorities, budgets, geographic, and organizational constraints. These differences cause agencies to select different equipment for data collection, use different data collection plans, and emphasize different data reporting outputs. The TMG provides support to highway agencies in regard to successful approaches for data collection, analysis, and reporting based on noteworthy practice examples. These noteworthy practice examples are highlighted in the appendices.

ES.4 MANUAL ORGANIZATION

The TMG begins with an overview of traffic monitoring programs (Chapter 1). The TMG also covers vehicle detection theory and provides an overview of different traffic monitoring technologies (Chapter 2) and provides comprehensive guidance on the methodologies used for motorized and micromobility traffic monitoring practices (Chapter 3). Defined record formats used for submitting traffic data for both motorized and micromobility data, along with a table explaining the deadlines for submitting traffic data to the FHWA Office of Highway Policy Information, can be found in Chapter 4. Federal data reporting requirements and the importance of HPMS reporting requirements for traffic data are explained in Chapter 5. The final chapter (Chapter 6) contains new information on acquiring third-party traffic data, new technology, and data analysis (3^rd Party Data Sources).

A glossary of terms, list of acronyms, and Appendices are included. The Appendices provide establishing data QA/QC criteria, setting up and calibrating data collection equipment, guidance on the use of traffic data for pavement design purposes, guidance on length-based classification, and traffic data quality control (QC) checks performed by the Travel Monitoring Analysis System (TMAS) software. The TMG also includes References.

There are several new sections within the 2022 TMG edition. These new sections with major changes are highlighted below and include:

• Expansion of non-motorized traffic monitoring to include all micromobility devices (Ch. 1 and 2)
• Consolidation and update of traffic monitoring technologies (Ch. 2)
• Similarities between motorized vehicle and micromobility data collection and processing (Ch. 3)
• Significantly revised data formats for FHWA submissions (Ch. 4)
• New emphasis on 3rd party roles in traffic programs (Ch. 6)

The 2022 TMG has been organized into six different chapters including the following:

• Chapter 1 Traffic Monitoring Theory, Technology and Concepts
• Chapter 2 Traffic Data Collection and Technology
• Chapter 3 Traffic Monitoring Methodology
• Chapter 4 Traffic Monitoring Formats
• Chapter 5 Federal Data Reporting Requirements and Tools: TMAS, HPMS
• Chapter 6 Third Party Traffic Data

Appendices in the TMG provide additional guidance to the user. The appendices are introduced briefly in section ES.5.

ES.5 SUPPORTING INFORMATION – APPENDICES OVERVIEW

• Appendix A – Vehicle Types (This appendix contains descriptions of 13 FHWA vehicle classes.)
• Appendix B – TMAS Quality Control Checks (This appendix provides quality checks for micromobility, volume, speed, class, weight, and IVR.)
• Appendix C – Compendium of Data Quality Control Criteria (This appendix contains compilation of data quality control (QC) criteria and QC checks used by Vermont and New York DOTs.)
• Appendix D – Equipment Calibration (This appendix contains compilation of successful traffic monitoring equipment calibration used by different highway agencies.)
• Appendix E – NCDOT Clustering Method for MEPDG Equipment Calibration (This appendix contains results of the research study that applied the clustering methodology to develop Traffic Data Inputs for Mechanistic-Empirical Pavement Design Guide (MEPDG).)
• Appendix F – Traffic Data for Pavement Design (This appendix describes the procedures for computing traffic inputs for traditional (AASHTO 93) and new MEPDG methods.)
• Appendix G – Length-Based Class Memo (This appendix describes the requirements for reporting of length-based vehicle classification data to the HPMS.)
• Appendix H – Bicycle and Pedestrian Site Selection Process/Publication - Florida Department of Transportation (FDOT's) Nonmotorized Site Selection Methodology (This appendix includes excerpts from the FDOT's 2018 Statewide Non-Motorized Traffic Monitoring Program Recommendations Report.)
• Appendix I – Motorcycle Data Collection Methods (This appendix provides detailed guidance for motorcycle data collection prepared by Montana DOT.)
• Appendix J – Traffic Pattern Examples (This appendix provides examples of temporal traffic patterns for motorized and micromobility travel including hourly, day of week, and monthly patterns for different road facility types.)
• Appendix K – Typical Interchange AADT Estimation (This appendix provides equations and computational examples to obtain AADT from limited mainline counts for the most common interchange and ramp configurations.)
• Appendix L – AASHTO AADT Calculation (This appendix provides equations to obtain AADTs using the AASHTO method.)
• Appendix M – Double Threshold WIM Array (This appendix provides the FHWA-preferred WIM array to use.)