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Center Identification Number:  6402-1041-00   

Project Title:  Assessing Air Quality Impacts of Managed Lanes

Principal Investigators:

Pei-Sung Lin, Ph.D., Director of ITS, Traffic Operations and Safety
Phone: 813-974-4910

Center for Urban Transportation Research
University of South Florida
Fax: 813-974-5168


Amy Stuart, Ph.D., Assistant Professor
Department of Environmental and Occupational Health and
Department of Civil and Environmental Engineering
University of South Florida
Phone: 813-974-6632

External Project Contact:     

Amy Datz
State Transit Environmental Planner
(850) 414-4239

I.  Start and End Dates

Start Date:  May 2009               Expected End Date: March 2010

I.  Project Objective/Problem Statement

The concept of managed lanes in transportation management is currently of significant interest around the U.S. due to its potential to mitigate traffic congestion and generate revenue.  The concept uses variable pricing of tolls to ensure desired operating speeds of vehicles using the managed lane facilities.  The resultant reduction of congestion is particularly important to the efficiency, visibility, and use of transit services.  Public buses, car pools, and van pools, which are allowed use of the managed lanes for waived or reduced fees, can then experience virtually unimpeded flow.  Increased utilization of transit options is expected to result from successful implementation of managed lane concepts.  Therefore, the National Center for Transit Research has targeted analysis of the design and performance of managed lane projects as a focus of study.

The Florida Department of Transportation has recently implemented a managed lane project in south Florida through the Miami Urban Partnership Agreement.  This agreement includes 21 miles of managed High Occupancy Toll (HOT) lanes on the I-95 corridor between Miami and Fort Lauderdale.  The federal government is also providing millions of dollars for new buses and Bus Rapid Transit (BRT) service on the I-95 corridor.  As the current express buses on I-95 are often substantially slowed in congestion, the HOT managed lane project is expected to enhance the speed of the BRT service network and lead to increased use of transit on the corridor.

In addition, transportation systems are currently a significant source of air pollutant emissions throughout the U.S. (Environmental Protection Agency, 2001).  Transportation infrastructure and management projects must now often consider the air quality impacts (National Research Council, 2004).  However, there is significant controversy over the impacts of transportation infrastructure and management projects on emissions and resultant air quality impacts (Transportation Research Board, 1995; Replogle, 1995; Dowling et al, 2005).  Hence, it is important to evaluate the potential benefits and costs of transportation projects on air quality. The I-95 managed lane project provides an opportunity to evaluate these impacts and develop methods for assessment applicable to future projects.

II.  Objectives/Tasks

The overall goals of this research are to evaluate the potential impacts of managed lane transportation projects on air quality and to develop methods for better determination of actual impacts.  To achieve these goals, we focus here on a case study of the Miami to Fort Lauderdale I-95 managed lane project.  We develop and use data analysis, emission calculation, and air quality modeling methodologies.  The specific objectives and supporting tasks that will be pursued are discussed below.

Objective 1:  Assess baseline air quality and temporal trends in air quality based on available air quality monitoring data.

Task 1:  Collect and compile baseline air quality trends for Miami-Dade and Broward counties

Annual air quality reports will be collected from the counties and state of Florida for the most recent three years since 2000.  Trends in the Air Quality Index, concentrations of ozone (O3), nitrogen dioxide (NO2), carbon monoxide (CO), particulate matter (PM2.5 and PM10) will be compiled.  Information on volatile organic compounds (VOCs) (or the similar categories of reactive organic gases (ROGs) or hydrocarbons (HCs)) will also be collected, when available.  Finally, available information on a few select air toxics related to mobile sources (e.g. benzene, acetaldehyde, and butadiene) will also be compiled.  Completion of this task is expected in months 1 to 2 of this research project.

Task 2:  Collect and compile available regulatory and special purpose monitoring data for the I-95 corridor

Data will be obtained for monitoring locations within 5 miles of I-95 between Miami and Fort Lauderdale from the USEPA AirData database, which collects and disseminated monitoring data.  Available averaging time summary data for the three most recent years since 2000 for O3, NO2, CO, PM2.5, PM10, VOCs, a few mobile source air toxics will be the focus.  Supplemental data will also be solicited directly from the counties and state of Florida for monitoring sites and/or pollutant information not available through the USEPA data.  Trends in reported averaging time concentration values will be plotted and summarized.  ArcGIS may be used to visualize the spatial distribution of pollution, if time allows. This task will be performed in months 3 to 4 of the research project.

Task 3: Perform comparison and write up of progress and results

Trends from summary reports data and available monitoring data will be compared and discussed.  This task will be ongoing, with substantial contributions during months 4 and 15-18.

Management:  Tasks for this objective will be performed by Dr. Stuart’s graduate student and will be supervised by Dr. Stuart. 

Objective 2:  Determine the mobile source emissions changes due to the managed lane project for select pollutants.

Task 1: Identify traffic micro-simulation software packages that can provide emissions from vehicles in a format that is compatible with dispersion models discussed in Objective 3

The traffic micro-simulation software will be used to estimate the emissions from vehicles on the I-95 corridor. Emissions are estimated by such models based on vehicle fleet characteristics, default emission rates and vehicle speeds on different sections of the roadway.  The emission data obtained from micro-simulation models will then be used in Objective 3 to assess the impact on air quality on the region.  The traffic micro-simulation software identified will have the capability to simulate multiple features of the I-95 corridor including managed lanes.  The task will be performed in months 1 to 2 of the research project.

Task 2:  Select and set-up an appropriate micro-simulation model

Microscopic simulation models simulate the movement of individual vehicles based on car-following and lane-changing theories. These models are effective in evaluating newly implemented transportation policy, 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. (Traffic Analysis Tools Program: FHWA).   The project team will inquire the FDOT to obtain the developed models for the study corridor.  The model will be assessed and evaluated to see if it can meet the need of the project. Limited further calibration and validation efforts will be conducted if necessary.  This task will be performed during months 3 to 5 of the research project.

Task 3: Calculate baseline emissions levels (prior to managed lane implementation) through simulation

The  simulation model output will be produced and provide emission data for hydrocarbons, oxides of nitrogen, and carbon monoxide.  Estimation of particulate matter will also be explored. Typically, emission levels are provided for different sections of the roadway in terms of grams per mile emitted for the duration of the simulation period.  These emission levels will form the baseline emissions for the I-95 corridor. Baseline transit use numbers on the corridor and the contribution of transit to pollutant emissions will also be calculated.  This will be performed during months 6 to 9 of the research project.

Task 4: Calculate emission levels by simulating managed lane implementation

The changes in the roadway geometry (such as addition of lane(s) or exit ramp restrictions etc.) and traffic management (HOV restrictions) will be incorporated in the model to simulate the managed lane implementation.  Depending on the timeline of the managed lane construction project and this research project, the managed lane implementation may also be calibrated based on the limited available field data. The running of this managed lane model will provide the emission levels for the managed lane implementation.  Effects of the managed lane implementation on corridor transit use numbers and the contribution of transit to pollutant emissions will also be calculated.  This will be performed during months 10 to 12 of the research project.

Task 5: Perform comparison and write-up of progress and results

A report will be developed to show the comparison of the baseline emissions with emissions under managed lanes operation emission along with other measure of effectiveness such as delay, travel time changes, and transit use.  This task will be ongoing, with substantial contributions during months 4, 7, 10, 13, and 15-18.

Management:  This task will be performed by CUTR staff. Specifically by a graduate student and Dr. Chanyoung Lee, supervised by Dr. Pei-Sung Lin.

Objective 3:  Determine modeled air pollutant concentration changes due to managed lane project.

Task 1: Select a dispersion modeling system

This will include review of characteristics of different dispersion modeling systems for calculation of air pollutant concentrations downwind of roadway sources.  Compatibility with emissions calculation models, discussed in objective 2, will also be a consideration.  Calpuff and Aermod, which are USEPA sanctioned models, are likely candidate models.  This task will be performed in months 5 to 6 of the research project.

Task 2: Set up the dispersion model for modeling air quality effects of a portion of the I-95 corridor

This will include downloading and setting up the model on the appropriate computing system.  Meteorological data will be gathered and implemented for the most recent year with available US EPA National Emissions Inventory (NEI) emissions data prior to the project.  Submodels, parameter values, and receptor locations along the corridor will be selected and set.  Mobile source parameters and emissions information will be based on data calculated for Objective 2 and the NEI mobile source data for the respective counties.  The pollutant focus will be CO, NOx, and one air toxic (if data are available).  Spatial allocation and NEI data will be investigated.  Appropriate mobile source buoyancy factors will be selected and implemented. This task will be performed in months 7 to 10 of the research project.

Task 3: Perform simulations to determine pollutant concentrations near the corridor. Simulations will be performed for baseline conditions and a simple “after” scenario

Based line condition data will be as described above.  A simple “after” scenario, representing conditions after the implementation of the managed lane project will also be run, using emissions data determined in Objective 2.  For the “after” scenario, all other conditions will remain the same to isolate effects of project. This task will be performed in months 11 to 15 of the research project.

Task 4: Comparison and write-up of progress and results

Progress on work task and results form the “before” and “after” scenarios for air pollutant concentrations will be discussed and compared.  The impact of transit use changes on air quality via emissions changes will also be discussed.  This task will be ongoing, with substantial contributions during months 7, 10, 13, and 15-18.

Management: Tasks for this objective will be performed by Dr. Stuart’s graduate student and will be supervised by Dr. Stuart.

Work not included in this scope of service is not to be performed and will not be subject to compensation by the Department.

Outcomes:  Through Objective 1, baseline trends in air quality parameters (pollutant levels and air quality index) relevant to the managed lane project will be determined and analyzed based on available monitoring data.  Outcomes of Objective 2 include the selection of a micro-simulation model for emissions determination from managed lane projects that is compatible with an air dispersion model.  Results for baseline emissions and for a managed lane scenario for the corridor will also be provided and compared to characterize air emissions changes due to the project, with a specific focus on the impacts due to transit use changes.  Emissions calculations will further allow calculation of air pollutant concentration changes through Objective 3.  Outcomes of Objective 3 include selection of a dispersion model for determine air quality impacts and results for corridor related air pollutant concentrations for baseline conditions and a managed lane scenario.  This will characterize likely impacts of the managed lane project on air quality.

Overall results will provide detailed characterization of baseline conditions of air quality, based on available air quality monitoring data, micro-simulation emissions estimation, and air dispersion pollutant modeling.  Results will also provide initial predicted effects of the managed lanes project on air quality (based on micro-simulation emissions and air dispersion modeling), and the contribution of changes in transit use.  Furthermore, methods and tools will be developed here for micro-simulation modeling of emissions, and air dispersion modeling of pollutant concentrations due to a managed lane project.  We anticipate implementing these methods along with intensive passive field sampling during a future project period for detailed study of “after” (post implementation of the managed lane project) scenarios and impacts of management selections (e.g. use of metering) on air quality parameters.  The methods developed and demonstrated here can also be used for future studies to assess the impacts of other managed lane projects.

III. Deliverables

Progress Reports: The university will submit quarterly progress reports to the Research Center. The first report will cover the activity that occurred in the 90 days following the issuance of the Task Work Order.

Reports should be submitted within 30 days of the end of the reporting period. Reports are due even if little or no progress has occurred (in which case, the report should explain delays and/or lack of progress). Progress reports should be sent in MS Word to Sandra Bell,

Progress reports must include the following information:

1.      Contract Number, Task Work Order Number, and Title

2.      Work performed during the period being reported

3.      Work to be performed in the following period

4.      Anticipated modifications (i.e., to funding, schedule, or scope). This section is for reporting/informational purposes, not for officially requesting an amendment. Note: To request an amendment to a contract, the contractor must provide the project manager with the appropriate information (i.e., what is being requested with justification) in the required format. If the project manager concurs with the request, he/she shall forward it with his/her approval and commentary, as appropriate, to the Research Center for administrative review and processing (pending available funds, etc.)

5.      A Progress Schedule (figures A, B, and C) updated to reflect activities for the period being reported.

Failure to submit progress reports in a timely manner may result in termination of the work order.

Draft Final Reports The draft final report will be submitted to Sandra Bell,  It should be edited for technical accuracy, grammar, clarity, organization, and format prior to submission to the Department for technical approval. The Research Center expects contractors to be able to provide well-written, high-quality reports that address the objectives defined by the scope of service.  Draft final reports must be prepared in accordance with the Guidelines for Preparing Draft Final and Final Reports ( This document provides information on all report requirements, including format requirements, the technical report documentation form, disclaimer language, and so forth.

The draft final report will be submitted by 90 days prior to the end of the task work order, allowing 30 days for review by the FDOT project manager, and 60 days for revision by the PIs and final review by the FDOT project manager.

Final Reports Once the draft final report has been approved, the university shall prepare the final report. The university will deliver a minimum eight (8) copies of the final report in MS Word on CD and one (1) unbound original, no later than the end date of the task work order, to

The Florida Department of Transportation

Research Center, MS 30

605 Suwannee Street

Tallahassee, FL 32399-0450

Each copy will be provided on a CD or DVD (i.e., for a total of eight disks). If the project manager requires additional copies, such provision must be indicated in the scope.

The project manager will review the final report to insure that all issues identified for correction in the draft final report have been addressed.

Power Point Presentation  A Power Point presentation will also be prepared on project methods and results.  This will be delivered with the final report.

Project Certification The Sponsored Research office or appropriate authority will submit as a final deliverable a project certification prepared according to university compliance standards.

A kickoff meeting shall be scheduled to occur before any work begins. As a minimum, the project manager and the principal investigator will attend. The Research Center staff must be advised of the meeting and given the option to attend. Other parties may be invited, as appropriate. The subject of the meeting will be to review and discuss the project’s tasks, schedule, milestones, deliverables, reporting requirements, and deployment plan.  The meeting will occur via teleconference.

IV.  Project Schedule


V.  Project Budget

Salaries and Fringe                                      72,741.18

Equipment                                                           400.00

Expenses                                                          1,200.00

Tuition                                                               14,400.00

Travel                                                                  1,600.00

Total Direct Costs                                          90,341.18

Indirect Cost (fixed price subtotal x 10%)     9,034.12

Total Project Cost                                          99,375.30

Project-necessary general research material and supplies will include computing supplies (needed electronic storage and software acquisition or licensing fees for traffic and air quality simulations and results visualization), field materials, project-necessary books, manuscripts, and other document acquisition fees, and teleconferencing fees for meetings with FDOT.

V.  Use of Graduate Student(s) and Other Research Assistants

One graduate student research assistant will perform the bulk of the monitoring data analysis and air dispersion modeling work, under the direction and close supervision of the Dr. Stuart.  The graduate student will be selected through advertisements in the Center for Urban Transportation Research, College of Engineering, and College of Public Health.   College-level coursework in advanced mathematics, chemistry, and computer programming will be required of the selected student, as these are necessary for the project work.

A second graduate student assistant from CUTR will assist to prepare and perform traffic simulation analysis on the I-95 corridor with and without managed lanes, and obtain associated emission data from simulation output under the direction and supervision of Dr. Lin and Dr. Lee.

VI.  Equipment

A camcorder with a tripod will be purchased for recording traffic flow and assessing traffic counts in order to validate the traffic simulation model.

Reimbursement will only occur upon receipt of and only for the amount of the purchasing invoice for the subject equipment.

The university, upon receipt of any purchased equipment, shall forward to the Research Center a copy of the purchase invoice/property description as detailed in Exhibit C – Budget/serial number and receipt. The Department will prepare and forward inventory control label(s), which the university shall have affixed to the property.

VII.  Travel

CUTR faculty members and a graduate assistant will travel to Miami to collect necessary data for microscopic traffic simulation before and after the implementation of the managed lane phases.  This travel is important for ground verification and selection of the traffic simulation model. Several major parameters of the model such as geometrics of I-95, all interchanges layouts within the project scope, locations and lengths of separator between of the managed lanes and general travel lanes, characteristics of traffic flow, traffic volume, vehicle type distribution, and travel time in traffic simulation model require a detailed field inspection and verification.  Without field verification, the researchers may not be able to confidently resolve problems encountered during the simulation runs and interpret the result of the simulations.  Three trips to Miami are expected due to three different stages of the implementation, Phase 1A: NB from SR 112 to Golden Glade Interchange (Summer 2009), Phase 1B: NB/SB from I-395 to Golden Glade Interchange, and Phase 2: NB/SB Full System from Golden Glade Interchange to I-595/Broward Park-n-Ride (Winter 2010).

All travel shall be in accordance with Section 112.061, Florida Statutes. FDOT employees may not travel on research contracts.

All travel is to be approved in advance in writing by the Department’s Project Manager.  The approval should include the method of travel (air, rental car, university vehicle), hotel cost, per diem, etc. for each person traveling.  A copy of the request and approval shall be provided to the Research Center and become a part of the official file.


National Center for Transit Research · at the Center For Urban Transportation Research · University of South Florida · 4202 E. Fowler Ave., CUT100 · Tampa, FL 33620-5375 · (813) 974-3120 · (813) 974-5168 · · Comments: