1.0 Introduction

This report presents the results of the United States Department of Transportation (U.S. DOT) Federal Highway Administration (FHWA) study of methods for before-after measurement of the travel and environmental impacts resulting from congestion pricing projects. Congestion pricing encompasses a variety of strategies which feature transportation facility charges to reduce demand during congested periods, such as high occupancy toll (HOT) lanes which allow vehicles with fewer occupants to pay a charge to access lanes available to vehicles with more occupants at no charge or at a reduced charge.

This report presents a summary and analysis of current before-after practices as well as a set of recommended practices for evaluating the environmental impacts of deployed congestion pricing projects. The summary of current practice is based primarily on a review of published literature pertaining to eight congestion pricing projects from around the world.

The remainder of this introductory chapter provides background information, elaborates on the purpose of this study and summarizes the study methodology. Chapter 2.0 presents narrative summaries of each of the eight study projects describing, for each project, the congestion pricing project, the travel and environmental impact evaluation methodologies, and the reported impacts. Chapter 3.0 draws upon the information presented in Chapter 2.0 to summarize the state-of-the-practice and presents a critical assessment of the strengths and weaknesses. Chapter 4.0 presents the recommended framework for before-after evaluations of the environmental impacts of congestion pricing projects.

1.1 Background and Purpose

Traffic congestion has proven to be a persistent, challenging problem throughout the world. Very significant levels of traffic congestion have persisted and, typically, have continued to increase in many urban areas over the last several decades. The Texas Transportation Institute analyzes traffic congestion data from agencies throughout the United States and publishes results in Urban Mobility Monitoring Reports. The latest available report¹, published in 2009 and based on 2007 data, show the following congestion increases between 1982 and 2007:

• 162 percent increase in annual congestion delay per traveler
• 427 percent increase in total delay
• 462 percent increase in total fuel wasted
• 422 percent increase in the total cost of congestion.

Although advances in transportation facilities and operations practices have proven useful in the effort to manage traffic congestion, to date, no cost-feasible and politically and environmentally acceptable “solutions” to traffic congestion have been identified. In approximately the last decade, the search for additional strategies to reduce traffic congestion has led to a heightened focus on congestion pricing. Interest in congestion pricing strategies is also, to some degree, a function of increasing interest in roadway revenue collection and financing options—the two strategies can be closely linked. Table 1‑1 identifies various types of congestion pricing projects and some examples of deployed projects and studies. The categories of congestion pricing projects used in Table 1‑1 are those used by the FHWA in their Value Pricing Pilot Program.²

 

Table 1-1. Types of Congestion Pricing Projects

Type of Congestion Pricing	Summary Description	Project or Study Examples
HOT Lanes (Partial Facility Pricing)	Conversion of high-occupancy vehicle (HOV) lanes into priced lanes called HOT lanes.  Vehicles not meeting HOV occupancy requirements can pay a fee to use the HOT lane.	I-15 in San Diego, California I-394 and I-35 in Minneapolis, Minnesota I-25 in Denver, Colorado I-95 in Miami, Florida I-10 and US 290 in Houston, Texas SR 167 in Seattle Washington I-495 in Virginia I-15 in Salt Lake City, Utah I-85 in Atlanta, Georgia
Express Toll Lanes (Partial Facility Pricing)	Introduction of new roadway capacity that can be accessed only by paying a toll.	SR 91 in Orange County, California
Full Roadway Facility Pricing	Introduction of variable tolls on roads, bridges or tunnels that were formerly free, or making currently flat tolls variable.	San Joaquin Hills Toll Road in Orange County, California Midpoint and Cape Coral Bridges in Lee County, Florida New Jersey Turnpike New York-New Jersey Interstate toll crossings SR 520 Bridge in Seattle, Washington
Zone-based Pricing, including Cordon and Area Pricing	Variable or fixed charges to drive within or into a congested area within an urban region.  Involves placing new tolls on multiple existing roads.	Central Congestion Charging The Stockholm Trial, Sweden Milan, Italy “EcoPass” Rome, Italy
Regionwide Pricing	Pricing at several locations within a region, including new and existing lanes or entire facilities.	Singapore
Making Vehicle Use Costs Variable	Conversion of fixed costs such as auto insurance into costs that vary by vehicle miles driven.	Oregon Mileage Fee Concept and Road User Fee Pilot Program Puget Sound Traffic Choices Study Commute Atlanta Mileage Based Value Pricing Demonstration Minnesota Mileage-based User Fee Demonstration
Parking Pricing and Other Market-Based Strategies		Dynamically Priced Car Sharing in Tampa, Florida New York City On-Street Parking Pricing San Francisco Car Sharing Los Angeles ExpressPark Variable Parking Pricing San Francisco Downtown Parking Pricing

 

 

An important manifestation of the increasing focus on congestion pricing in the United States is the U.S. DOT Urban Partnership Agreement (UPA) and Congestion Reduction Demonstration program. Under the UPA/CRD, U.S. DOT has provided a total of approximately $1B shared among six metropolitan areas (Atlanta, Los Angeles, Miami, Minneapolis, San Francisco and Seattle) to deploy integrated sets of congestion reduction strategies that feature various forms of congestion pricing coupled with supporting travel demand management, transit, and technology-based strategies. Table 1‑2 summarizes the UPA/CRD deployments, with the congestion pricing strategies shown in bold type. An important part of the UPA/CRD program is the U.S. DOT evaluation of the impacts of each deployment. Comprehensive assessments of the impacts of the various strategies used at each site are critical both to inform U.S. Federal transportation policy and programs but also to provide guidance to operating agencies who may implement similar strategies.

As congestion pricing projects are becoming more common there is a growing volume of literature describing the projects and their effects. However, there is little published literature on the strengths and weaknesses of prevailing congestion pricing evaluation methodologies. This study is intended to address that deficiency; to summarize current practice and recommend a framework that can inform the UPA/CRD evaluations that are currently in progress and which may also help guide future U.S. DOT or other evaluations.

The primary focus of this study is on the environmental impacts of congestion pricing, including air quality, noise and environmental justice. However, environmental impacts are typically a direct result of travel impacts of projects, such as changes in traffic volumes and roadway speeds. As such, it was clear that this study must also consider how the travel impacts which underlie environmental impacts have been and can best be evaluated.

1.2 Study Process

The study process consisted of the following steps:

• A scan of published literature on congestion pricing projects
• Selection of study projects for detailed literature review
• Detailed review of published literature on the study projects
• Review of several general (not evaluation methodology-focused) congestion pricing references for possible information on evaluation
• Development of the state-of-the-practice summary and recommended framework.

The initial scan of published literature utilized extensive Internet-based literature searches as well as some searches of university library and technical journal databases. The initial scan was intended to provide a sketch-level understanding of the number and general nature of congestion pricing projects and studies of those projects worldwide. That understanding also informed the selection of a manageable number of study projects.

 

Table1-2. Summary of UPA/CRD Strategies by Site³

UPA/CRD Strategies	Site
	MN	SF	Sea	Mia	LA	Atl
Convert HOV lanes to dynamically priced high-occupancy tolling (HOT) lanes and/or new HOT lanes	X			X	X	X
Priced dynamic shoulder lanes	X
Variably priced parking and/or loading zones		X			X
Variably priced roadways or bridges (partial cordon)			X
Increase park-and-ride capacity (expand existing or add new)	X		X	X	X	X
Expand or enhance bus service	X		X	X		X
Implement new, or expand existing, Bus Rapid Transit	X			X	X
Transit on special runningways (e.g., contraflow lanes, shoulders)	X			X
New and/or enhanced transit stops/stations	X		X	X	X
Transit traveler information systems (bus arrival times, parking availability)	X	X	X
Transit lane keeping/lane guidance	X
Transit traffic signal priority	X			X	X
Arterial street traffic signal improvements to improve transit travel times	X
Ferry service improvements		X	X
Improved transit travel forecasting techniques		X
Pedestrian improvements				X	X
“Results Only Work Environment” employer-based techniques	X
Work to increase use of telecommuting	X	X	X	X
Work to increase flexible scheduling	X		X	X
Work to increase alternative commute programs, including car and van pools	X	X	X	X	X	X
Vehicle infrastructure integration test bed		X
Active traffic management	X		X
Regional multi-modal traveler information (e.g., 511)	X	X	X
Freeway management (ramp meters, travel time signs, enhanced monitoring)	X			X
Enhanced traffic signal operations	X
Parking management system		X			X
Integrated electronic payment for parking and transit		X
Automated enforcement of HOV and toll violations						X

Note: Strategies shown in bold type are congestion pricing strategies.

 

A number of conclusions were drawn based on the initial scan:

• A large number of congestion pricing projects was found—about 70, too many to study in-depth as part of this study, and therefore a down-selection of study projects was necessary.
• There was significant variation in congestion pricing projects in terms of the type of pricing (HOT lane, cordon, area, etc.), geographic location (there are many U.S. and international projects), deployment status (proposed/planned vs. operating), and consideration of environmental impacts.
• There was a limited amount of literature focusing on the before-after evaluation of the environmental impacts (including the precipitating travel impacts) of congestion pricing projects. The authors of a 2008 FHWA evaluation of their Value Pricing Pilot Program⁴ reached the same conclusions.

The following compiled lists of congestion pricing projects include the projects considered in the initial scan conducted for this study and are available on-line:

• A list compiled by Mark W. Burris, Ph.D., P.E. of the Texas Transportation Institute: https://ceprofs.civil.tamu.edu/mburris/pricing.htm
• A list of Federal Highway Administration Value Pricing Pilot Program Projects: https://ops.fhwa.dot.gov/tolling_pricing/value_pricing/projects/allprojects.htm
• A list of case studies examined through the Coordination of Urban Road User Charging Organisational Issues (CURACAO) program (see “Case Studies” list): http://www.curacaoproject.eu/downloads.php.

Following the initial scan, a subset of congestion pricing projects was selected for detailed literature review based on consideration of the following factors:

• A focus on analyses of deployed, operational congestion pricing projects (whether a short-term demonstration with simulated congestion charges or long-term, full deployment with real charges)—which is consistent with the fundamental study objective to inform the evaluation of the UPA/CRD field deployments.
• The apparent extent to which environmental impacts were considered.
• The desirability of including several highly visible, frequently cited pricing and/or revenue collection projects like the London, Singapore and Stockholm area pricing schemes and the Puget Sound and Oregon field studies.
• A mix of pricing projects reflecting a variety of pricing strategies.
• A mix of projects from throughout the United States and around the world.

Based on these factors, along with practical considerations encountered over the course of the research—namely difficulties in finding sufficient documentation for certain projects—the following eight study projects were selected.

• Oregon Mileage Fee Concept and Road User Fee Pilot Program
• Puget Sound Traffic Choices Study
• Commute Atlanta Mileage Based Value Pricing Demonstration
• Minnesota I-394 MnPASS HOT Lanes
• San Diego I-15 HOT Lanes
• The Stockholm Trial
• Central London Congestion Charging
• Singapore Area Pricing.

Three of these projects—the Oregon, Puget Sound and Atlanta projects—consisted of before-after (or “with/without”) evaluations of short-term field demonstrations of congestion pricing/revenue collection schemes featuring simulated pricing charges. The other projects all consisted of before vs. after evaluations of fully-deployed congestion pricing schemes with real pricing charges. The eight study projects and associated evaluation methodology and pricing impact results information gleaned from the literature review are described in Chapter 2.0.

After selecting the eight study projects, a second on-line literature search was conducted to obtain as many relevant project documents as possible. In addition to reports focusing on specific congestion pricing projects, this second search identified a small number of congestion pricing synthesis reports, including the following:

• FHWA, Value Pricing Pilot Program Lessons Learned, Final Report (August 2008)
• CURACAO reports (State of the Art Review, May 2009; Final Report, June 2009)
• FHWA, Lessons Learned from International Experience in Congestion Pricing (December 2008).

All of this project-specific and synthesis literature was analyzed and provides the basis for Chapters 2.0 and 3.0 of this report, and informs the recommendations presented in Chapter 4.0.

 

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¹ Schrank, David and Lomax, Tim, “Urban Mobility Monitoring Report 2009,” University Transportation Center for Mobility, Texas Transportation Institute, July 2009.

² United States Department of Transportation, Federal Highway Administration, “Report on the Value Pricing Pilot Program Through May 2009,” September 17, 2009.

³ United States Department of Transportation, Federal Highway Administration and Federal Transit Administration, “Atlanta Congestion Reduction Demonstration National Evaluation Plan – Draft,” prepared by Battelle, May 2010.

⁴ United States Department of Transportation, Federal Highway Administration, “Value Pricing Pilot Program: Lessons Learned Final Report.” Prepared by K.T. Analytics and Cambridge Systematics, Inc. August 2008.