Office of Operations
21st Century Operations Using 21st Century Technologies

An Interim Guidebook on the Congestion Management Process
in Metropolitan Transportation Planning

3.0 Basics of the CMP


This section presents the foundation of the CMP based on over a decade of experience developing Congestion Management Systems (CMS). The CMP, while it builds upon previous practice and on the congestion management system first required under ISTEA, differs in significant ways from the CMS and from congestion management “plans.” The CMP is intended to be an integral part of the planning process together with to the metropolitan transportation plan. The goals and objectives from the MTP feed directly into the beginning steps of the CMP. The CMP also has an increase emphasis on incorporating management and operations in the process. Figure 3 presents the framework on which the CMP is formed.

Figure 3. CMP Framework (the “8 Steps”)

Figure 3 - graphic - This figure shows the flow of the eight steps of the CMP including: develop congestion management objectives, identify area of application, define system/ network of interest, develop performance measures, institute system performance monitoring plan, identify/ evaluate strategies, implement selected strategies/mange system, and monitor strategy effectiveness.   From the eight steps there are influences of integrate with MTP, TIP, and other efforts as well as apply to the scale of the region.
“Congestion Management objectives” relate specifically to the Congestion Management Process, but other objectives – focused on operations, land use, system preservation, and other regional priorities – can be derived from the vision and goals articulated in the metropolitan transportation plan. The essential elements of getting from Goals to Strategies are described below with illustrative examples specific to congestion management objectives.


Goals describe in broad terms what the region wants to accomplish, focused on outcomes.

Example: Reduce congestion by improving transportation system reliability and reducing unexpected traveler delay.

Congestion Management Objectives

Objectives are specific steps that help to accomplish the goal, and include outcome or output-oriented measures. Objectives should be stated such in a way that performance measures (see below) can be derived from the objectives. Congestion management objectives may be related to other, operations-oriented objectives, such as making transit more attractive to commuters, or to objectives aligned with regional land use goals. Examples may include:

  • Reduce incident-based delay (so that by 2010…);
  • Reduce traveler delay associated with work zones, weather conditions, and special events (so that…);
  • Improve access to travel information (so that…); and
  • Improve transit system reliability (so that…)

Performance Measures

Performance measures provide metrics that can be used at a regional basis to track systemwide performance (used in developing a regional objective), or at a corridor, roadway, or intersection level to identify specific deficiencies within the system. Examples may include:

  • Incident duration (mean minutes per incident);
  • Vehicle hours of non-recurring delay due to incidents;
  • Total vehicle hours of non-recurring delay;
  • Buffer time (additional time to ensure travelers arrive at destination by intended time 95 percent of the time);
  • Person throughput (number of persons traversing a corridor, summed across all travel modes, over a specified period of time);
  • Public awareness of traveler information (through surveys);
  • Public satisfaction with level of information available (through surveys);
  • Public satisfaction with regional/corridor travel speeds and times (through surveys)
  • Percentage of buses more than five minutes off schedule; and
  • Number of rail system breakdowns/delays.


Selected projects and programs are implemented in order to achieve objectives. These strategies may include capacity enhancement, safety projects, management and operations, system preservation. Examples specific to the objective of improving system reliability and reducing traveler delay include:

  • Roving incident response teams;
  • Work zone information campaign;
  • Variable message signs to alert about alternative routes;
  • Traveler alert system;
  • 511;
  • Electronic real-time “next bus” information at bus stops;
  • Increased rail inspections and maintenance;
  • GPS systems to track transit buses; and
  • Strategic combinations of any or all of the above.


The CMP comprises a number of different elements that add up to a coherent, objectives-driven, performance based approach to solving congestion problems. These components are described in the Final Rule on Statewide and Metropolitan Transportation Planning. The Rule states that the CMP shall include:

1. Methods to monitor and evaluate the performance of the multimodal transportation system, identify the causes of recurring and non-recurring congestion, identify and evaluate alternative strategies, provide information supporting the implementation of actions, and evaluate the effectiveness of implemented actions;

2. Definition of congestion management objectives and appropriate performance measures to assess the extent of congestion and support the evaluation of the effectiveness of congestion reduction and mobility enhancement strategies for the movement of people and goods. Since levels of acceptable system performance may vary among local communities, performance measures should be tailored to the specific needs of the area and established cooperatively by the State(s), affected MPO(s), and local officials in consultation with the operators of major modes of transportation in the coverage area;

3. Establishment of a coordinated program for data collection and system performance monitoring to define the extent and duration of congestion, to contribute in determining the causes of congestion, and evaluate the efficiency and effectiveness of implemented actions. To the extent possible, this data collection program should be coordinated with existing data sources (including archived operational/ITS data) and coordinated with operations managers in the metropolitan area;

4. Identification and evaluation of the anticipated performance and expected benefits of appropriate congestion management strategies that will contribute to the more effective use and improved safety of existing and future transportation systems based on the established performance measures. The following categories of strategies, or combinations of strategies, are some examples of what should be appropriately considered for each area:

  1. Demand management measures, including growth management and congestion pricing;
  2. Traffic operational improvements;
  3. Public transportation improvements;
  4. ITS technologies as related to the regional ITS architecture; and
  5. Where necessary, additional system capacity;

5. Identification of an implementation schedule, implementation responsibilities, and possible funding sources for each strategy (or combination of strategies) proposed for implementation; and

6. Implementation of a process for periodic assessment of the effectiveness of implemented strategies, in terms of the area’s established performance measures. The results of this evaluation shall be provided to decision-makers and the public to provide guidance on selection of effective strategies for future implementation (23 CFR 450.320(c)).


Step 1 – Develop Congestion Management Objectives

As noted in Section 3.1, congestion management objectives derive from the vision and goals articulated in the MTP. The vision and goals are likely to be developed early in the planning process, but the development of congestion management objectives may help to sharpen and focus the goals established in the MTP.

While the goals in the MTP may be couched in general terms, congestion management objectives should be defined in terms that enable participants in the process to focus on specific aspects of congestion, and to advance a timeframe within which the objectives would be attained. For example, congestion management objectives may be different for commute trips than for other travel purposes. Alternatively, objectives may be established for peak period travel as opposed to off-peak travel.

Specific congestion management objectives might also be developed for freight movement, and may be focused on activity areas or corridors where the movement of goods is particularly important, such as a port, terminal and warehousing district, or freight corridor. Such objectives could refer to achievement of the goals by a certain date, or in more general terms, such as “By the end of the decade.”

Step 2 – Area of Application

A congestion management process should be applied to a specific geographic area and network of surface transportation facilities. Often an area of application may align with the same geographic area contained in the Regional ITS Architecture. This alignment would allow system inventories and network descriptions to directly link to the CMP to the Regional ITS Architecture. As previously noted, “acceptable” levels of system performance may vary by type of transportation facility, geographic location, and time, including time of day and weekday/weekend patterns.

In TMAs, the geographic limits of the CMP must encompass at least the TMA boundary. It would be advantageous to include the entire metropolitan area boundary, which is the TMA boundary plus the area that will become urbanized within twenty years, or some other rational criteria, such as the limits of an air-quality non-attainment area. In non-TMA MPOs, the preferential CMP boundary would most likely be the MPO planning area boundary. In areas where significant facilities or activity centers border the limits of a given metropolitan area, it may be appropriate to expand the CMP boundaries to include a broader analysis area.

Step 3 – System Definition

Whatever the geo-political boundaries of the CMP, the CMP network should identify the characteristics of the surface transportation network under consideration. The CMP should be multimodal, so the network should include both highway and transit facilities. Depending upon the nature of the region, and the congestion problems experienced by system operators, it may be appropriate to incorporate freight facilities such as marine or airport facilities, as well as rail transportation assets (commuter or intercity passenger as well as freight) that may be subject to congested conditions.

The CMP could consider particular corridors or activity centers, in addition to encompassing an entire metropolitan area. A CMP may also comprise a combination of regional, corridor, and activity area definitions, with each component serving different, specific purposes.

Characteristics of Good Performance Measures:

  • Clarity and simplicity (e.g., simple to present and interpret, unambiguous, quantifiable units, professional credibility)

  • Descriptive and predictive ability (e.g., describes existing conditions, can be used to identify problems and to predict changes)

  • Analysis capability (e.g., can be calculated easily and with existing field data, techniques available for estimating the measure, achieves consistent results)

  • Accuracy and precision (e.g., sensitive to significant changes in assumptions, precision is consistent with planning applications and with an operation analysis)

Flexibility (e.g., applies to multiple modes, meaningful at varying scales and settings)

Step 4 – Developing and Using Performance Measures

The use of performance measures to assess the effectiveness and efficiency of the transportation network and of operations has greatly increased in recent years. Many of these measures are designed for more effective communication both with members of the public and with appointed and elected officials. Rather than using highly technical measures such as level of service, measures such as speed, travel time, and delay are employed to describe mobility and access at various levels, from the entire regional system to particular corridors, and even at the route or intersection level. A number of recent reports provide useful information on performance measures, including the Final Report of the National Transportation Operations Coalition (NTOC) Performance Measurement Initiative (July 2005), which identified a handful of performance measures commonly accepted by Federal, state, and local transportation officials.

  • CMP performance measures should be derived from the vision, goals, and objectives established for the region during the metropolitan transportation planning process. The CMP itself is designed to put into action the vision and goals defined in the planning process by transforming goals into specific objectives, identifying where goals are not being achieved, and coming up with strategies that will help to achieve these goals. The CMP also provides ways to follow up and determine whether the strategies are contributing to success.
  • Define for the region what congestion means, and what indicators best illustrate the impact of congestion on travelers and on economic activity. Recognize also that the best indicators or criteria may change over time.
  • Review the most commonly used performance measures, and consider those that have been identified as the most useful. Appendix B lists a number of measures, including measures particularly suited to performance-based planning.

Table 1. Performance Measures from NTOC Performance Measures Initiative Final Report



Sample Units of Measurement

Customer Satisfaction

A qualitative measure of customers’ opinions related to the roadway management and operations services provided in a specified region.

Very satisfied/Somewhat satisfied/Neutral/Somewhat dissatisfied/Very dissatisfied/Don’t know/Not applicable

Extent of Congestion –Spatial

Miles of roadway within a predefined area and time period for which average travel times are 30 percent longer than unconstrained travel times.

Lane miles of congested conditions or % of congested roadways.  Calculated as a ratio = 100% x (Cong. Lane Miles)/(Total Lane Miles)

Extent of Congestion – Temporal

The time duration during which more than 20 percent of the roadway sections in a predefined area are congested as defined by the “Extent of Congestion – Spatial” performance measure.

Hours of congestion

Incident Duration

The time elapsed from the notification of an incident until all evidence of the incident has been removed from the incident scene.

Median minutes per incident

Non-Recurring Delay

Vehicle delays in excess of recurring delay for the current time-of-day, day-of-week, and day type.


Recurring Delay

Vehicle delays that are repeatable for the current time-of-day, day-of-week, and day type.



The average speed of vehicles measured in a single lane, for a single direction of flow, at a specific location on a roadway.

Miles per hour, feet per second, or kilometers per hour

Throughput – Person

Number of persons including private vehicle occupants, transit riders, pedestrians, & bicyclists traversing a roadway section in one direction per unit time – by mode.  May also be the number of persons traversing a screen line in one direction per unit time.

Persons per hour

Throughput – Vehicle

Number of vehicles traversing a roadway section in one direction per unit time.  May also be number of vehicles traversing a screen line per unit time.

Vehicles per hour

Travel Time – Link

The average time required to traverse a section of roadway in a given direction.

Minutes per trip

Travel Time – Reliability (Buffer Index)

The Buffer Time is the additional time that must be added to a trip (measured as defined by Travel Time – Trip) to ensure that travelers making the trip will arrive at their destination at, or before, the intended time 95 percent of the time.

Minutes.  This measure may also be expressed as a percent of total trip time or as an index.

Travel Time – Trip

The average time required to travel from an origin to a destination on a trip that might include multiple modes of travel.

Minutes per trip

  • Adopt key performance measures relevant to the operations objectives and to the congestion problems facing the region. Most regions use a variety of measures to identify congested locations and to track system performance over time.
  • Include multimodal measures. For example, measures related to highway congestion should be accompanied by those related to transit, goods movement, and non-motorized modes.
  • Recognize that performance measures can be applied flexibly. Different levels of congestion, for instance, may be acceptable in different places and at different times.

Development of performance measures based on regional operations objectives is discussed in more detail in section 4.3 below, and in the accompanying Guidebook, Management and Operations in the Metropolitan Transportation Plan. Performance measures and analytical tools are also discussed in Appendix B of this document.

Step 5 – Developing a Performance Monitoring Plan

Historically, the availability of data has been one of the greatest challenges facing planners and system operators. With the advent of ITS technology for freeway and arterial management, detector data is increasingly available for major facilities in many metropolitan areas. Transit data is also increasingly available from advanced public transportation systems applications such as automatic vehicle location systems, which can provide information about schedule delay and on-time performance for transit.

Even greater quantities of information are likely to be available as next-generation systems utilizing Vehicle-Infrastructure Integration (VII) come on line over the next decade. Full deployment of VII depends upon a mutual decision of the public and private sectors, expected before 2010, but the deployment process will take some time to reach a critical mass. Nevertheless it is worthwhile to consider the potential impacts on transportation data availability of ubiquitous data collection from individual vehicles through a nationwide communications network. An unprecedented level of data on vehicle location and trajectories could be available in near-real time for both operational and planning purposes.

The Final Rule on Metropolitan Transportation Planning calls for “a coordinated program for data collection and system performance monitoring to assess the extent of congestion, to contribute in determining the causes of congestion, and evaluate the efficiency and effectiveness of implemented actions.” Data collection needs are based on the selected performance measures and appropriate analytical methods. The selected data elements should be relevant to the area, readily available, timely, reliable, consistent, and susceptible to forecasting. The Final Rule also directs that “To the extent possible, this data collection program should be coordinated with existing data sources (including archived operational/ITS data) and coordinated with operations managers in the metropolitan area.” If data required to track system performance is unavailable, either on a regional or local level, the data collection and system monitoring program should indicate how data collection capabilities will be enhanced over time.

Common sources of data include traditional methods such as travel surveys and screenline counts; traffic counts, whether from temporary or permanent count stations for the Highway Performance Monitoring System; ITS traffic detection devices; aerial surveys; and speed studies. ITS components may collect useful data for operational purposes, so it would be advisable to make use of the ITS Regional Architecture to identify sources of such data. Since data may be made available from a number of different agencies in a given region, it is important to either establish common data formats or to establish a process for converting data from disparate sources into a single dataset for use in the CMP. This process may already be underway in regions where archived ITS data is in use for operational or planning purposes.

Step 6 – Identifying and Evaluating Strategies

Identifying Congested Locations

Selection of the appropriate performance measures, analytical tools, and available data enables the identification of congested locations. Congestion may be recurring or non-recurring; the CMP should be capable of analyzing both types of congestion. Recurring congestion, which takes place at predictable intervals at particular locations, can generally be traced to a specific cause, such as a physical bottleneck or to conditions such as sun glare. Causes of non-recurring congestion may be more difficult to isolate, and solutions may require non-traditional strategies.

In addressing recurring or non-recurring congestion, the CMP might incorporate different levels of analysis, whether at the regional, corridor, or activity area scale. Ongoing data collection and monitoring is helpful in determining the effectiveness of strategies and the utility of the CMP itself. This issue will be visited again when we discuss the need for monitoring and evaluating the congestion management process.

Selecting Appropriate Analytical Tools

A variety of traffic analysis tools have been developed for different purposes. These tools are intended for application at different geographic scales, for different facility types, by travel mode, and according to the type of management strategy under consideration. Therefore, it is important to select analysis tools that are sensitive both to the congestion measures to be used and the types of congestion management strategies under consideration. The traffic analysis tools may also assess different traveler responses, according to different performance measures, and with different levels of resources required. The FHWA provides information about the characteristics of these tools and guidelines for selecting the appropriate tools on its Traffic Analysis Tools web site ( Traffic analysis tools can be grouped into the following categories:

  • Sketch-Planning Tools – Sketch-planning methodologies and tools produce general order-of-magnitude estimates of travel demand and traffic operations in response to transportation improvements. They allow for the evaluation of specific projects or alternatives without conducting an in-depth engineering analysis. Therefore, sketch-planning approaches are typically the simplest and least costly of the traffic analysis techniques.
  • Travel Demand Models – These are mathematical models that forecast long-term future travel demand based on current conditions and future projections of household and employment characteristics. Travel demand models were originally developed to determine the benefits and impact of major highway improvements in metropolitan areas. Travel demand models only have limited capabilities to accurately estimate changes in operational characteristics (such as speed, delay, and queuing) resulting from implementation of ITS/operational strategies.
  • Analytical/Deterministic Tools (HCM-Based) – Most analytical/deterministic tools implement the procedures of the Highway Capacity Manual (HCM). As such, these tools quickly predict capacity, density, speed, delay, and queuing on a variety of transportation facilities. These tools are good for analyzing the performance of isolated or small-scale transportation facilities; however, they are limited in their ability to analyze network or system effects.
  • Traffic Signal Optimization Tools – Similar to the analytical/deterministic tools, traffic optimization tool methodologies are mostly based on the HCM procedures. However, traffic optimization tools are primarily designed to develop optimal signal phasing and timing plans for isolated signal intersections, arterial streets, or signal networks. This may include capacity calculations; cycle length; splits optimization, including left turns; and coordination/offset plans.
  • Macroscopic Simulation Models – Macroscopic simulation models are based on the deterministic relationships of the flow, speed, and density of the traffic stream. The simulation in a macroscopic model takes place on a section-by-section basis rather than by tracking individual vehicles. Macroscopic simulation models were originally developed to model traffic in distinct transportation subnetworks, such as freeways, corridors (including freeways and parallel arterials), surface-street grid networks, and rural highways.
  • Mesoscopic Simulation Models – Mesoscopic models combine the properties of both microscopic (discussed below) and macroscopic simulation models. As such, mesoscopic models provide less fidelity than microsimulation tools, but are superior to the typical planning analysis techniques.
  • Microscopic Simulation Models – Microscopic simulation models simulate the movement of individual vehicles based on car-following and lane-changing theories. These models are effective in evaluating heavily congested conditions, complex geometric configurations, and system-level impacts of proposed transportation improvements that are beyond the limitations of other tool types. However, these models are time consuming, costly, and can be difficult to calibrate (from FHWA Office of Operations web site,

CMP Strategies

The managers of the congestion management process should consider the full range of potential strategies. Strategies can be grouped into the following broad categories:

1. Adding More Base Capacity – Increasing the number and size of highways and providing more transit and freight rail service. This can include expanding the base capacity (by adding additional lanes or building new highways) as well as redesigning specific bottlenecks such as interchanges and intersections to increase their capacity. This approach is not always possible due to constraints both physical and fiscal, but it remains an important approach to addressing congestion, alone and in combination with other strategies. It should also be noted that, in TMAs designated as nonattainment for ozone or carbon monoxide, expansion of facilities that would provide significant additional capacity for single occupancy vehicles (SOVs) cannot proceed using Federal funds unless “analysis demonstrates that travel demand reduction and operational management strategies cannot fully satisfy the need for additional capacity in the corridor and additional SOV capacity is warranted (23 U.S.C. 450.320 (e)).” Given the expense and possible adverse environmental impacts of adding new SOV capacity, due consideration should be given to travel demand management and operational measures before electing to add capacity, rather than improving the utilization of existing capacity.

  • Key Strategies:
    • Adding travel lanes on major freeways and streets (including truck climbing lanes on grades);
    • Adding capacity to the transit system (buses, urban rail or commuter rail systems);
    • Closing gaps in the street network;
    • Removing bottlenecks;
    • Overpasses or underpasses at congested intersections;
    • High-occupancy vehicle (HOV) lanes; and
    • Increasing intercity freight rail capacity to reduce truck use of highways.

2. Operating Existing Capacity More Efficiently – Getting more out of what we have. Rather than building new infrastructure, many transportation agencies have embraced strategies that deal with the operation of the exiting network of highways transit systems, and freight services. Many of these operations-based strategies are enhanced by the use of enhanced technologies or ITS. (It should be noted that ITS projects must come from a regional ITS architecture. The relationship between the CMP and the regional ITS architecture is discussed in more detail in Section 4.4.)

  • Key Strategies:
    • Metering traffic onto freeways;
    • Optimizing the timing of traffic signals;
    • Faster and anticipatory responses to traffic incidents;
    • Reserved travel lanes or rights-of-way for transit operation;
    • Realigned transit service schedules and stop locations;
    • Providing travelers with information on travel conditions as well as alternative routes and modes;
    • Improved management of work zones;
    • Identifying weather and road surface problems and rapidly targeting responses;
    • Providing real-time information on transit schedules and arrivals;
    • Monitoring the security of transit patrons, stations, and vehicles;
    • Anticipating and addressing special events, including emergency evacuations, that cause surges in traffic;
    • Better freight management, especially reducing delays at border crossings;
    • Reversible commuter lanes;
    • Congestion pricing strategies, including high occupancy toll (HOT) lanes;
    • Movable median barriers to add capacity during peak periods;
    • Restricting turns at key intersections;
    • Geometric improvements to roads and intersections;
    • Converting streets to one-way operations; and
    • Access management.

3. Encouraging Travel and Land Use Patterns that Use the System in Less Congestion Producing Ways – Travel Demand Management (TDM), non-automotive travel modes, and land use management. These strategies provide options that result in more people traveling in fewer vehicles, or trips made in less congested times. In some instance the goal is to substitute communications for travel, or to encourage regional cooperation to change development patterns and reduce sprawl.

  • Key Strategies to Address Congestion:
    • Programs that encourage transit use and ridesharing;
    • Curbside and parking management;
    • Flexible work hours;
    • Telecommuting programs;
    • Bikeways and other strategies that promote non-motorized travel;
    • Pricing fees for the use of travel lanes by the number of persons in the vehicle and the time of day;
    • Pricing fees for parking spaces by the number of persons in the vehicle, the time of day or location;
    • Land use controls or zoning;
    • Growth management restrictions such as urban growth boundaries;
    • Development policies that support transit-oriented designs for corridors and communities involving homes, jobsites, and shops; and
    • Incentives for high-density development, such as tax incentives.

Step 7 – Implementation and Management

This step involves the implementation and management of the defined strategies. Managers of the CMP should work closely with the operating agencies that have participated in the CMP process throughout the implementation of congestion management strategies and activities. At this step information developed through the CMP should be applied to establish priorities in the Transportation Improvement Program thereby facilitating the implementation of the congestion management process. This ensures a linkage between the CMP and funding decisions, either through a formal ranking and weighting of strategies and projects, or through other formal or informal approaches.

Step 8 – Monitoring Strategy Effectiveness

Managers of the CMP should periodically evaluate the effectiveness of strategies identified through the CMP. It is essential that the analysts utilize the performance measures developed through the CMP to determine the effectiveness of the selected strategies. In assessing the degree to which the CMP strategies addressed the problems of congestion, it is important to also assess the issue of how well, and to what extent the strategies were implemented, and to consider confounding factors that may have contributed to the success or failure of the selected projects or programs.

A decision to measure results requires a plan to collect pre-implementation data, as well as make preparations for an ongoing monitoring process, as discussed in Step 4 above. The ongoing monitoring process should be able to isolate those marginal changes in system performance that may be associated with the improvement.

Based on the feedback from the assessment process, the MPO should make appropriate adjustments to their effectiveness forecasting process and the CMP itself. These adjustments may be with respect to the strategies considered, or may reflect back to the performance measures used; the data collection and management component of the process; or the analytical methods and tools applied. The CMP should be subject not only to periodic review, but to a timetable for upgrading the tools and methods to keep pace with current practice.


The FHWA and FTA continue to work with their partners in the metropolitan planning community to provide information and obtain feedback on the emerging planning practices. In preparation of publication of the Rule on Statewide Transportation Planning: Metropolitan Transportation Planning, FHWA had sponsored a series of workshops designed to inform stakeholders about emerging requirements and to gauge the reactions of practitioners to the new playing field.

In February 2006, FHWA sponsored a Peer Exchange workshop involving MPOs and state DOTs in a review of their experiences with congestion management systems and processes as currently configured. This workshop evolved into the “Congestion Management Processes Peer Exchange and Case Studies” project (July, 2006). The workshop examined several key topics, including linkage of CMP with NEPA documentation, operations, and performance measures; coordination of the CMP with transit agencies; interagency coordination; and the use of CMP for setting priorities and evaluating project impacts.

The consensus of the planning practitioners involved in the Peer Exchange was that a transition from congestion management “systems” to a congestion management “process” makes sense – but none of the participants thought that the transition would be easy. Even in regions where congestion management has been an integral part of the process for years, there is still skepticism about what a CMS or CMP can contribute to solving a region’s congestion problems.

Still other projects have focused on the challenges inherent in measuring, monitoring, and responding to congestion in metropolitan regions. One such study, “Traffic Congestion and Reliability – Trends and Advanced Strategies for Congestion Mitigation” (Cambridge Systematics, Inc. and Texas Transportation Institute, 09/01/2005) offered insight into how the causes, measurement, and monitoring of congestion vary in different settings, and focused on congestion trends and implications for the future. This report emphasized the need for linking the planning process and the practice of transportation systems management and operations, and the need to make effective use of the data and analytical tools now available for assessing patterns of congestion.

In the wake of SAFETEA-LU and the new transportation planning requirements ushered in by that legislation, the FHWA sponsored workshops to review the new requirements and to focus on congestion management processes. The “SAFETEA-LU Planning Provisions Workshop” (prepared for FHWA and the American Association of State Highway and Transportation Officials (AASHTO) Standing Committee on Planning by Cambridge Systematics, May, 2006) covered the spectrum of planning requirements at the statewide level and a number of requirements at the metropolitan level, emphasizing areas of continuity and topics where new thinking has emerged. The Congestion Management Process was among the areas that both draw upon existing practice, and seek new approaches and greater integration with the rest of the metropolitan transportation planning process.

Many of the findings of the studies referred to above have been incorporated into this guidebook. It is also important to recognize the connections between the development of this guidebook and other, concurrent efforts. FHWA/FTA is also currently undertaking the development of a guidebook for management and operations in the planning process; documenting and assessing various analysis tools with applications to transportation systems management and operations; and cataloguing resources available for statewide transportation planning.

Other MPOs have incorporated innovative elements into their congestion management processes. The Delaware Valley Regional Planning Commission (DVRPC), the MPO for the Philadelphia, PA region, has tightened the linkage between their CMP and their TIP by integrating their CMP database with the TIP database. DVRPC expects to make it easy for users of their web site “to easily switch between the TIP and CMP pages to enhance understanding and planning.” CMP pages of the web site will incorporate clickable maps to allow users to access data, appropriate strategies, relevant adopted reports, and links to TIP projects for each congested subcorridor.” CMP corridors have been used in the development of the current MTP for the region, and the MPO plans an update of the CMP “to provide [a] technical basis for the next Plan.”

Current Practice: Developed congestion management systems anticipate the evolution of the CMP, congestion management processes as part of the long range metropolitan planning process. 

The Atlanta Regional Commission (ARC) has established a CMP designed to manage congestion throughout the Atlanta, Georgia region and to maximize the safety and mobility of people and goods.  The process involves four steps: 

  • Identification,
  • Understanding and Priority,
  • Implementation; and
  • Data and Monitoring.

The ARC analysis framework uses a Congestion Management System Network that covers the thirteen-county Atlanta region, as well as major facilities in five adjacent counties, incorporating interstate highways, HOV facilities, major roadways and select minor roads.  Congested locations are identified both through outputs of regional transportation models, using the Travel Time Index (TTI), and through field data collection in travel time studies. 

Congested locations are identified according to TTI, where moderate congestion is indicated by TTI levels of 1.35 to 1.80, and severe congestion is indicated by a travel time index greater than 1.80.  Once congested locations are identified, the CMP is used to help develop low-cost, high-impact solutions to congestion on the basis of regional priorities.  Different locations can have different thresholds for “tolerable” levels of congestion, based on activity and travel patterns; priorities are also determined in the context of the intensity, extent, and duration of congestion.  Analyses are undertaken in the form of corridor studies, focusing on the movement to and from activity centers from both facility and travelshed perspectives; and activity center analysis, which focuses on destination corridors and movement within activity centers. 

Data is obtained from a variety of sources, including Advanced Traffic Management System (ATMS) data obtained from the regional Traffic Management Center; aerial photography data; and information from studies such as the Metro Atlanta Signal Timing Project, corridor studies, and information retained from the region’s pre-existing congestion management system.  The ARC is currently in the process of enhancing their analysis tools, including incorporating the impact of crashes and weather on non-recurring congestion.  ARC planners are also establishing processes to track success through before and after studies where CMP mitigation strategies have been implemented.  For further information on ARC’s work please go to


Ultimately, the CMP is intended to be a flexible approach to transportation problem solving that builds upon years of experience in congestion management. Congestion management systems were first advanced in ISTEA. Even the ISTEA requirements built upon earlier efforts to focus on congestion, including research projects and such practical products as the Institute for Transportation Engineers’ (ITE) “A Toolbox for Alleviating Traffic Congestion.” The intent of the move to a “congestion management process” is evolutionary: to incorporate congestion management into the planning process, while retaining the flexibility to apply the CMP approach at all levels of the project and program development and delivery process. The CMP should enable transportation planners and decision-makers to apply the most appropriate and effective tools and strategies to address congestion from the regional level to location-specific improvement projects.

It is important to emphasize that the CMP is intended to support transportation decision making, as an integral part of the planning process. While the process may be supported by a program or system of data collection, monitoring, and analysis (a “congestion management system”), and may produce reports detailing alternative strategies and projects designed to address specific congestion problems (a “congestion management plan”), the CMP is a set of tools for identifying and addressing congestion throughout the long range planning and project development cycle. MPOs that have long-standing congestion management programs or systems may be challenged in the transition to a fully integrated long range transportation process that makes congestion management a “core” activity, as opposed to an isolated, stand-alone process. Even MPOs that have done an exemplary job of breaking down the “silos” that can separate elements of the planning process may face institutional barriers to fully integrating the CMP into the project development process, using CMP studies and products as part of the NEPA process. (This issue is discussed in more detail below.)

While there are many available technical methods that can assist in assessing the state of congestion in a given region, MPOs may be challenged in developing and maintaining these tools for their own regions. The ability to acquire and maintain the level of data collection and management is also a significant hurdle in many areas. Different operating agencies may have quite different and distinct data collection and management systems. Even if data is collected into a regional data archive, many of these differences in how each agency collects, processes, and formats data may remain. MPOs may encounter significant barriers in consolidating information and reconciling these different data management practices.

The difficulties inherent in understanding and using data from multiple agencies underscores the need to involve the appropriate players from transportation system operating agencies, both at the policy and technical level. These challenges apply as well to attracting and retaining professional staff to manage the CMP. While obtaining the necessary level of commitment and continuity of involvement from agency staff is a formidable challenge, bringing together operations personnel and policy level representatives from multiple operating agencies can also offer tremendous opportunities for creating formal and informal networks and working relationships. Creating a CMP “team” can deliver real benefits by transforming “stakeholders” into partners in pursuing effective congestion management strategies.

Notwithstanding these challenges, the CMP offers an opportunity to institutionalize a new and strategic mindset toward transportation issues. The objectives-driven, performance-based approach to metropolitan transportation planning embodied in the CMP, and in the new emphasis on management and operations, can strengthen the planning process by directing attention to short- and medium-term measures to mitigate congestion, as well as to measures that will maintain the safety and efficiency of new and expanded transportation facilities into the future. The CMP approach can also be a template for approaching other regional objectives that are established through the planning and visioning process.

The challenges and opportunities outlined above may present themselves to an MPO and the other participants in the CMP at any stage in the development of the congestion management process. Whether adapting an existing system or starting from scratch, the architects of the CMP will be implementing a process that builds on past experiences while incorporating an objectives-driven, performance based approach to addressing congestion.

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