II iii Assessing Air Quality Impacts of Managed Lanes

ii DISCLAIMER The opinions, findings, and conclusions expressed in this publication are those of the authors and not necessarily those of the State of Florida Department of Transportation. Impacts on transit bus performance and air quality were investigated for a case study high-occupancy / toll (HOT) lane project on a corridor of I-95 near Miami. Trends in air pollutant concentration monitoring data in the study area first were analyzed. Traffic movement prior to and after implementation of the HOT lanes was simulated using corridor micro-simulation (CORSIM). Emissions of carbon monoxide, nitrogen oxides, particulate matter, hydrocarbons, and benzene were estimated using MOBILE6.2. Finally, changes in ambient pollutant concentrations were estimated using AERMOD dispersion simulations. Results indicate decreased congestion on the corridor due to the HOT lane implementation, particularly for the northbound direction during the afternoon peak hours. Specifically, bus travel times were reduced by nine minutes, on average, during these hours. Emissions results were mixed, with small estimated increases for CO, NO x , PM 10 , and benzene and small decreases for HCs. Slightly higher ambient concentrations were found in most of the study area for the pollutants modeled (CO, NO x , and benzene), with the largest increases near the corridor. Overall, changes in both emissions and concentrations were small, indicating small impacts of the managed lane project on air quality. An additional outcome was the identification of factors contributing to uncertainty in the emissions estimation. Managed lanes are currently of significant interest for transportation management in the U.S. Resultant reductions in congestion are expected to have potential benefits for transit service use. Additionally, since transportation systems contribute substantially to air pollution, information on the impacts of managed lanes on air quality and methods to assess those impacts are needed. In this study, impacts on transit bus performance and air quality were investigated for a case study managed lane project. The case study project is the I-95 Express project managed by the Florida Department of Transportation through the Miami Urban Partnership Agreement. It involves conversion of a single high-occupancy vehicle (HOV) lane into two high-occupancy / toll (HOT) lanes along a corridor of I-95 between Miami and Fort Lauderdale. Objectives of this project were to: 1. assess air quality and temporal trends in air quality prior to the managed lane project, 2. determine emissions changes due to the managed lane project for select pollutants, and 3. determine modeled air …