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Florida Department of Transportation (FDOT) Express Toll Lane Modeling Workshop Peer Review Report

7.0 Panel Discussion and Observations

7.1 Demand Modeling Recommendations

The panel's responses to questions and subsequent discussions did not include a specific set of recommendations for FDOT's express lane demand model forecasting practice. However, as described in Section 5.0, panel members did discuss several basic modeling principles on which there was general agreement. These were reiterated on the morning of the second day of the workshop and form the guiding principles of a recommended practice for modeling express lanes in Florida to help insure the development of high quality and consistent forecasts. (Note that these recommendations do not specifically address simulation modeling.) These principles are discussed as follows.

  1. Consistency of Forecasts: The development of express lane forecasts is an evolutionary process, starting from a high-level screening process, continuing through more detailed corridor studies, and ending in detailed T&R forecasts that may support acquisition of private financing, investment-grade forecasts. Progressing from the early to final stages, each step requires a greater sophistication and rigor in the forecasting procedure, and a progressively greater need for detailed flow and observed behavioral data to support the model algorithms. The models used in each stage should, however, share common behavioral assumptions (e.g., value-of-time and toll policy) and, to the extent possible, differ in terms of level of detail and market segmentation. The models should build upon the earlier stages and not represent independent modeling approaches.
  2. Standard Evaluation Criteria: MOEs and evaluation criteria should be established and documented early in the project development phase. Ideally, these MOEs should be established for all FDOT projects to allow for objective evaluation of projects. Potential MOEs that models should be capable of reporting include, but are not limited to:
    1. Travel time savings
    2. Reliability
    3. Ability to meet express lane operations costs from tolls
    4. Congestion relief for general purpose and express lane users
    5. Transit impacts
    6. Other methods of quantifying user benefits for both general purpose and express lane users
  3. Use of State-of-the-Practice Model Features: A necessary, but not sufficient, requirement for models used to estimate express lane demand should be the inclusion of several state-of-the-practice features now incorporated in the latest FSUTMS "transit" model update, which include the following:
    1. Travel time and cost feedback, including trip distribution, mode choice and assignment steps.
    2. Use of destination-choice formulation for the distribution model.
    3. Expanded mode choice nesting structure, including a toll/non-toll choice for auto modes.
    4. Expanded time-of-day stratification in both distribution and mode choice and more detailed time-of-day stratification for trip assignment.
    5. Expanded trip purposes.
    6. Market segmentation involving income and auto sufficiency.
    7. Multi-class traffic assignment, by hour or period.
  4. Use of a Toolbox Approach to Model Design: A selection of managed lane modeling approaches, such as those described in the three-phase managed lane modeling structure developed at the FDOT Systems Planning Central Office, should be used to specify models for express lane evaluation. These tools include an integrated toll/non-toll binary choice and assignment model (Phase I); a toll choice nest within a mode choice model, potentially coupled with the Phase I assignment model; and an ABM using a daily activity scheduler and mode choice, coupled with a DTA model with at least 15-minute time intervals. As discussed in Item 1 above, use of these models should, to the extent possible, share consistent assumptions with regard to traveler value-of-time, toll policy, and facility design, with the understanding that more detail is required as the analysis progresses to the final stage.
  5. Inclusion of Reliability and Time-of-Day Model Sensitivities: To properly evaluate an express lane with open-road tolling variable pricing, forecast models should be sensitive to reliability and choice of time-of-day of travel, in addition to time savings and cost. These have been shown to be drivers of traveler responses to managed lanes. Both can be implemented even in traditional four-step models with static assignments. There should also be an explicit sub-model to balance demand and toll level.
  6. Robust Data Collection to Support Model Development: Data collection should include traffic volumes, speeds, O/D data, and household/transit rider characteristic information. SPSs or RPSs that identify a distribution of value-of-time by income, time-of-day, and trip purpose should also be collected as necessary. Data sources and needs should be identified as early as possible in a study, as advanced express lane forecasts will be needed and should be used to inform all phases of the model forecasts.
  7. Risk Analysis: In more advanced stages of project development, and essential to investment-grade forecasts, a risk analysis should be conducted. The risk analysis should reveal the project's particular sensitivities to variations in value-of-time, toll rates, future demand, fuel price, and economic development. This will allow decision-makers to properly evaluate the potential for success of each project.

More specific model features are discussed in NCHRP Report 722[3] which provides further guidance on model features and designs recommended for modeling priced managed lanes.

The first wave of tolled managed lanes in Florida has been studied and implemented over the past several years has been conducted during the FDOT project development process rather than being included as part of the long-range planning activities conducted by MPOs throughout the State. The unique demand modeling, traffic operation analysis, and toll revenue analysis aspects of these projects have been addressed by FDOT's Districts on a project-by-project basis.

In order to be prepared for the next wave of tolled managed lanes the following short-term and long-term recommendations are presented below. These recommendations cover demand modeling, traffic operations analysis, and T&R analysis.

7.2 Short-Term Operational Analysis Recommendations

The following short-term traffic operations analysis recommendations were provided by the Blue Ribbon Panel:

7.3 Long-Term Operational Analysis Recommendations

The following long-term traffic operations analysis recommendations were provided by the Blue Ribbon Panel:

Figure 7: Recommended Traffic Operations Analysis Components

Traditional Activities

Traffic Operations Analysis Supporting Express Lane Projects

Activities

Issues

Products

Data

Demand Input

Operational Tools

MPO

Regional Planning Studies

T&R Estimate

Lane call analysis for general purpose vs. express lanes; Location of ingress & egress points

Planning Study;  Level of Service and V/C ratios; Express Feasibility Report

Regional ConOps; Access Locations, Traffic: Off Peak Pd, Peak Pd, Peak Hr Traffic

Regional MPO Model

Generalized Tables & Spreadsheets or Microsimuation if Available

FDOT

Project Planning Studies

Level 1 Traffic Study

Lane call analysis for general purpose & express lanes; Location of ingress & egress points

Concept Traffic Report;  Level of Service and V/C ratios

Regional ConOps; Access Locations, Off Peak Pd, Peak Pd, Peak Hr Traffic, Origin-Destination Data, Speed Data

Regional MPO Model; Meso DTA Model

Regional: HCS-HCM
Corridor: HCS-HCM, Microsimulation

Project Development and Environmental Studies

Level 2 Traffic Study

Complete freeway facilities analysis including operating conditions at ingress/egress points

Traffic Technical Memorandum;  Level of Service; Density, Travel Speed, System-wide Delay, Throughput, Reliability

Corridor ConOps;Traffic counts; Origin-Destination Data; Speed Data

Project Validated Demand Model; Meso DTA Model

Microsimulation

Design Studies

Level 3 Traffic Study

Refined corridor analysis based on feedback from T&R study and design refinements

Interstate System Access Report;  Level of Service; Density, Travel Speed, System-wide Delay, Throughput, Reliability

Corridor ConOps;Traffic counts; Origin-Destination Data; Speed Data

Project Validated Demand Model;Meso  DTA Model; Corridor TOD Model

Microsimulation

7.4 Short-Term Toll & Revenue Analysis Recommendations

Historically, there is not a direct correlation between the FDOT's project development process and T&R studies. Additionally, there has been little effort to consider revenue for express lane projects at the MPO-level.

It is recommended that distinct T&R studies be conducted during each phase of the project development process. At the MPO-level, it would be acceptable for the MPO consultant to provide simplistic estimates of revenue for the purposes of using or recommending certain projects for advancement by the maintaining District. As a project advances into the FDOT project development process, the T&R studies should be completed by each District through the FTE. The FTE should work closely with the District program manager to determine whether the project is considered to be at planning-, PD&E-, or Design-level at every phase of the project development process.

Figure 8 shows the activities, issues, products, data and tools for T&R studies and how they should correlate to the FDOT's project development process.

Figure 8: Recommended Traffic Revenue Analysis Components

 

Traditional Activities

Traffic Operations Analysis Supporting Express Lane Projects

Activities

Issues

Products

Data

Demand Input

Operational Tools

MPO

Regional Planning Studies

T&R Estimate

Lane call analysis for general purpose vs. express lanes; Location of ingress & egress points

Planning Study;  Level of Service and V/C ratios; Express Feasibility Report

Regional ConOps; Access Locations, Traffic: Off Peak Pd, Peak Pd, Peak Hr Traffic

Regional MPO Model

Generalized Tables & Spreadsheets or Microsimuation if Available

FDOT

Project Planning Studies

Level 1 Traffic Study

Lane call analysis for general purpose & express lanes; Location of ingress & egress points

Concept Traffic Report;  Level of Service and V/C ratios

Regional ConOps; Access Locations, Off Peak Pd, Peak Pd, Peak Hr Traffic, Origin-Destination Data, Speed Data

Regional MPO Model; Meso DTA Model

Regional: HCS-HCM
Corridor: HCS-HCM, Microsimulation

Project Development and Environmental Studies

Level 2 Traffic Study

Complete freeway facilities analysis including operating conditions at ingress/egress points

Traffic Technical Memorandum;  Level of Service; Density, Travel Speed, System-wide Delay, Throughput, Reliability

Corridor ConOps;Traffic counts; Origin-Destination Data; Speed Data

Project Validated Demand Model; Meso DTA Model

Microsimulation

Design Studies

Level 3 Traffic Study

Refined corridor analysis based on feedback from T&R study and design refinements

Interstate System Access Report;  Level of Service; Density, Travel Speed, System-wide Delay, Throughput, Reliability

Corridor ConOps;Traffic counts; Origin-Destination Data; Speed Data

Project Validated Demand Model;Meso  DTA Model; Corridor TOD Model

Microsimulation

7.5 Conclusion

The Peer Review Express Toll Lane Modeling workshop ended after almost twelve hours of presentations and discussion. The FDOT and members of the Florida modeling community showed high levels of enthusiasm based on the various opportunities and ideas for future activities conferred in workshop discussions and presented by the Blue Ribbon Panelists. There need for innovations and standard best practices for managed lane modeling in the State is highly transparent, and the Peer Review facilitated an ideal forum for discussion of Statewide implementation considerations.


[3] NCHRP Report 722: Assessing Highway Tolling and Pricing Options and Impacts, Volume 2: Travel Demand Forecasting Tools. National Cooperative Highway Research Program, Transportation Research Board. 2012. Chapter 7 pp. 153-157.http://onlinepubs.trb.org/onlinepubs/nchrp/nchrp_rpt_722v2.pdf

Updated: 03/28/2014
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