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21st Century Operations Using 21st Century Technologies

Incorporating Travel-Time Reliability into the Congestion Management Process (CMP): A Primer

Chapter 3. Getting Started

This chapter provides a checklist for agencies to use to get started on incorporating reliability into their Congestion Management Process (CMP).

Integrating Reliability into the Metropolitan Transportation Plan

SHRP 2 L05 - Incorporating Reliability Performance Measures into the Transportation Planning and Programming Process: A Guide [7] is a useful resource for integrating reliability into both the MTP and CMP.

3.1 Update Goals, Objectives and Performance Measures

  1. Assess current goals, objectives, and performance measures.
    1. Ensure alignment with Moving Ahead for Progress in the 21st Century Act (MAP-21) performance rule for reliability.5
  2. Work with stakeholders to develop reliability goals, objectives, and performance measures (see Chapter 2.1).
    1. Develop a business case(s) for including reliability in the CMP as well as the metropolitan transportation plan (MTP).
    2. Conduct a pilot analysis of a prominent facility to test various reliability metrics and determine which metrics are most applicable and to educate stakeholders on how reliability can be applied.
    3. Review proposed changes with stakeholders.
  3. Refine goals, objectives and performance measures to incorporate reliability based on stakeholder feedback.

3.2 Assess Data Needs and Availability

  1. Review current data collection program against recommendations in Chapter 2.2. If satisfactory, skip remaining sub steps and proceed to Step 3.3.
  2. Check with local and national data sources to obtain one year of travel-time data along with corresponding incident logs, traffic counts, and other event conditions such as weather and construction.
    1. The National Performance Management Research Data Set (NPMRDS) contains 5-minute travel-time data for freeways going back go October 2011 and for NHS roadways going back to July 2013.
    2. Transportation management centers (TMCs) may have archived data for select facilities from system detectors, toll tag readers, Bluetooth readers, or other probe measurements.
    3. Private vendors: check to see if your state department of transportation (DOT) has purchased 3rd party travel-time data.
  3. If data are not available, refer to the second Strategic Highway Research Program (SHRP 2) resources for estimating reliability using predictive tools.

3.3 Diagnose Causes of Unreliability for Select Facilities

  1. Review current methods for identifying and diagnosing the causes of reliability problems against recommendations in Chapter 2.2. If satisfactory, skip remaining sub steps and proceed to Step 3.4.
  2. Select facilities for analysis that are prone to reliability impacts, including:
    1. Highly congested facilities;
    2. Major freight routes;
    3. Corridors of major significance (bridges, tunnels, etc.);
    4. Routes that serve high volumes of seasonal recreational traffic;
    5. Routes subject to inclement weather (snow, ice, and visibility);
    6. Routes that receive complaints by system users; and
    7. Routes in metropolitan areas designated under the Real-Time System Management Information Program.
  3. Select time of day (morning or evening peak-period) and days of year for reliability analysis.
  4. Calculate reliability performance measures identified in 3.1.3 for facilities selected in 3.3.2.
  5. Diagnose causes of unreliability following recommendations in Chapter 2.2:
    1. Demand fluctuation;
    2. Incidents;
    3. Weather;
    4. Special Event; and
    5. Construction.

3.4 Evaluate and Prioritize Reliability Strategies

  1. Compare current method for identifying, evaluating, and prioritizing reliability improvement strategies against guidance in Chapters 2.3 and 2.4. If satisfactory, skip remaining sub steps and proceed to Step 5.
  2. Identify strategies to address causes of unreliability (see Tables 4 and 5).
  3. Assess benefits, costs, and level of impact (see Table 6).
  4. Set targets consistent with MAP-21.

3.5 Prepare CMP Update

  1. Option 1: Annual Update
    1. An annual update is not required, but may be desirable because it provides an opportunity to the metropolitan planning organization (MPO) to assess progress on achieving its targets. The performance of various strategies and actions that have been implemented is assessed for effectiveness. The CMP may be modified to focus on the most-effective strategies.
    2. Assess if the CMP is integrated into the MTP.
  2. Option 2: Major Update
    1. A major update should be considered after adoption of the MTP (every 4 or 5 years depending on air quality attainment status).
      • Did the MTP goals and objectives change regarding the priority of congestion mitigation and recognition of non-recurring congestion?
      • Did baseline conditions change?
      • Are new analytic techniques available?
Table 7. Getting Started Checklist
Steps and Actions No Action to Date Beginning to Make Progress Partially Achieved Mostly Achieved Fully Achieved
Update Goals, Objectives and Performance Measures
Have the existing goals, objectives, and performance measures been reviewed?
Have measures been evaluated for compliance with MAP-21 Performance Measures for Reliability?
Has stakeholder input and support been gathered/achieved?
Assess Data Needs and Availability
Has the current data collection program been reviewed against reliability data requirements?
Have supplemental local and national data sources been investigated?
Have SHRP 2 tools been identified to perform predictions?
Diagnose Causes of Unreliability for Select Facilities
Have current methods for diagnosing reliability problems been investigated?
Have facilities been identified that may be prone to reliability problems?
Have the temporal conditions for reliability analysis been defined?
Have reliability performance measures been calculated?
Have the causes of unreliability by facility been diagnosed?
Evaluate and Prioritize Reliability Strategies
Have current prioritization methods been reviewed for applicability to reliability-based evaluations?
Have strategies been identified to address causes of unreliability?
Have benefits, costs and level of impacts been assessed?
Have performance targets been set consistent with MAP-21?
Prepare CMP Update
Has the type of CMP Update been identified (annual or major update)?
Have the necessary steps been taken to perform the update?

5 Rule-making at the national level had not been released as of the date of this publication.


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