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Air Quality

Recent Developments

Listed below are recent developments pertinent to air quality from the past six months.  If you would like to suggest a recent development on this topic, please submit a short description to AASHTO (including any pertinent links) on the Share Info with AASHTO form.

• EPA Report: Estimating Emission Reductions from Travel Efficiency

  The Environmental Protection Agency has issued a report summarizing use of its Travel Efficiency Assessment Method (TEAM) for estimating transportation emission reductions. TEAM uses transportation sketch modeling, travel activity data sets, and EPA’s MOVES emissions model to estimate the potential future emission reductions from combinations of travel efficiency strategies. Such strategies include employer-based transportation management programs, transit improvements, smart growth and related land use strategies, road and parking pricing, and other strategies aimed at reducing vehicle travel. The agency also released two new case studies, one from Austin and one from Pittsburgh, applying TEAM in regional sketch planning. For more information, link here. (July 2020)

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• FHWA Announces Alternative Fuel Corridors Designations, Summary Report

  The Federal Highway Administration has completed the fourth round of designations for its Alternative Fuel Corridors program. With the designation of these corridors, FHWA is continuing to establish a national network of alternative fueling and charging infrastructure along national highway system corridors. FHWA also released a summary report of five regional Alternative Fuel Corridors Convenings held in 2018 and 2019. The report contains information and perspectives from across the country on the installation of alternative fuel infrastructure along highway corridors. For more information, link to the Alternative Fuel Corridors website. (6-24-20)

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• Group Compiles Resources on VW Settlement, Trust Fund

  The National Association of Clean Air Agencies has compiled a repository of state and local agency information and links pertaining to the Volkswagen (VW) settlement and the Mitigation Trust Fund. The information includes state and local agency webpages, public outreach materials, and documents. The fund was established as part of the settlement between the U.S. government and VW over the company’s alleged use of “defeat devices” designed to cheat on federal emission tests. The trust provides funding to each state for eligible projects that will reduce nitrogen oxides. For more information, link to the repository. (6-16-20)

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• American Lung Association Issues 2020 'State of the Air' Report

  The American Lung Association’s annual "State of the Air" report for 2020 finds that nearly half of the nation’s population – 150 million people – lived with and breathed polluted air, placing their health and lives at risk. The study – which identified climate change as an increasing factor impacting air quality – looked at the two most widespread outdoor air pollutants: ozone pollution and particle pollution. The 2020 found that more than 20.8 million people lived in counties that had unhealthy levels of air pollution in all categories from 2016 to 2018. It identified U.S. cities deemed most polluted as well as the cleanest cities. For more information, link to the announcement and the report. (4-21-20)

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• EPA Proposes to Revise Benefit-Cost Analyses under the Clean Air Act

  The Environmental Protection Agency has proposed regulations to revise requirements for benefit-cost analyses under the Clean Air Act. The goal of the proposal is to ensure that all future significant regulations promulgated under the act be accompanied by a benefit-cost analysis using the best available scientific information, in accordance with best practices from the economic, engineering, physical, and biological sciences, and ensuring transparency of the analysis. The agency also is soliciting comment on how to consider the results of a benefit-cost analysis in future rulemakings under specific provisions of the act, and how EPA should weigh the results of such analyses in future CAA regulatory decisions. Comments will be accepted for 45 days following publication in the Federal Register. For more information, link to the EPA fact sheet. (6-4-20)

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• FHWA Updates CMAQ Website with 'Project Spotlight'

  The Federal Highway Administration has updated its Congestion Mitigation and Air Quality Improvement Program website, including a “project spotlight” section that profiles CMAQ projects. As of 2015, the CMAQ program had provided more than $30 billion to fund over 30,000 transportation-related environmental projects. The FAST Act provided up to $2.5 billion in CMAQ funding for each year of the authorization-2016 through 2020. It emphasizes diesel engine retrofits including construction equipment, port-related landside non-road or on- road equipment, and alternative fuel infrastructure in designated corridors. For more information, link to the CMAQ web page.

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• FHWA Issues Alternative Fuel Vehicle Fleet Module for CMAQ Toolkit

  The Federal Highway Administration recently has issued a module for on-road alternative fuel vehicle fleet purchases for the Congestion Mitigation and Air Quality Improvement (CMAQ) Emissions Calculator Toolkit. The module allows users to quantify the potential emission reductions that might be achieved when a fleet converts to alternative fuel vehicles or advanced drivetrain technologies. The tool allows modeling of many passenger and commercial vehicle sources, but excludes others such as transit buses. The module, which includes a users’ guide and other documentation, provides information on the appropriate inputs into the Environmental Protection Agency's Motor Vehicle Emissions Simulator (MOVES2014b). For more information, link to the CMAQ Emissions Calculator Toolkit. (3-19-20)

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• Research Suggests Easing Congestion with Variable Speed, Lane Change Controls

  The use of intelligent transportation systems and variable speed limits can help to ease traffic congestion and bottlenecks, and reduce vehicle emissions, according to a policy brief from the National Center for Sustainable Transportation. The policy brief is based on findings from researchers at the University of Southern California who simulated traffic patterns and the use of variable speed limit and lane change control systems to evaluate the potential traffic impacts of these systems. The research suggests that reducing speed limits in real time and far in advance of traffic bottlenecks created by highway incidents, along with lane change control systems, can smooth the flow of traffic and handle larger volumes at lower speeds. For more information, link to the policy brief. (3-9-20)

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• Research Estimates Emission Reductions from Zero Emission Vehicles

  A research report that assesses the emissions impacts of nationwide zero emission vehicle (ZEV) adoption has been developed under the National Cooperative Highway Research Program (NCHRP Web-Only Document 274, NCHRP 25-25, Task 115). Researchers projected changes in emissions of criteria pollutants, mobile source air toxic pollutants, and greenhouse gases resulting from varying ZEV adoption scenarios with a 20-year time horizon. The objective of the report was to help readers to understand what key factors influence the degree to which ZEVs will impact the vehicle fleet emissions. For more information, link to the report. (2-3-20)

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• EPA Issues Emission Inventory Methods for Port and Goods Movement

  The Environmental Protection Agency has issued a draft document on how to develop port-related and goods movement emissions inventories. The document, Methodologies for Estimating Port-Related and Goods Movement Mobile Source Emission Inventories, has specific information on how to develop inventories for criteria pollutants and precursors, climate-related pollutants, mobile source air toxics, and energy consumption. The document applies to both offshore and onshore forms of transportation, including cargo handling equipment and onroad vehicles. Comments on the draft document can be submitted by March 31, 2020. For more information, link to the document. (2-4-20)

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• FHWA Issues Managed Lanes Module for CMAQ Toolkit

  The Federal Highway Administration has issued a new managed lane facilities and conversions module for the Congestion Mitigation and Air Quality Improvement (CMAQ) Emissions Calculator Toolkit. The module allows users to quantify the potential emission reductions that might be achieved from reduced freeway congestion through the addition or modification of a managed lane project such as high-occupancy vehicle (HOV), high-occupancy toll (HOT) lanes, and other forms of controlled access lanes on highways. The module, which includes a users’ guide and other documentation, provides information on the appropriate inputs into the Environmental Protection Agency's Motor Vehicle Emissions Simulator (MOVES2014b). For more information, link to the CMAQ Emissions Calculator Toolkit. (1-17-20)

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• EPA Issues Advance Notice on Heavy Truck Air Standards

  The Environmental Protection Agency is seeking public comments on an advance notice of proposed rulemaking on emission standards for heavy-duty vehicles. The Cleaner Trucks Initiative would establish new emission standards for oxides of nitrogen (NOx) for highway heavy-duty engines and would address certification procedures to reduce costs for engine manufacturers. For more information, link to the ANPR Web Page and related fact sheet. (1-13-20)

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• CMAQ Emissions Tool Transit Fleet Module Updated

  The Federal Highway Administration has released updates to modules of the Congestion Mitigation and Air Quality (CMAQ) Emissions Calculator Toolkit. The Transit Bus Service and Fleet Expansion module is one of a series of spreadsheet-based tools that can be used to facilitate the calculation of representative air quality benefit data, for CMAQ project justification, and annual reporting. Other modules recently updated include those for bicycle and pedestrian improvements, diesel idle reduction, transit bus retrofits, and carpooling. For more information, link to the toolkit. (12-12-19)

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• Guidance Updated for Fourth Round of Alternative Fuel Corridors

  The Federal Highway Administration has issued an updated question and answer document regarding the FAST Act Section 1413 Alternative Fuel Corridor Designations. The document covers general questions, questions specific to the four different rounds of designations, fuel-specific questions, questions about signage, coordination with the Energy Department, and resources such as FHWA contacts and information about the Alternative Fuel Corridor Convenings. The document has been updated in connection with the fourth round request for nominations. For more information, link to the FAQ. (12-3-19)

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• Demand Management Scheme Wins Clean Air Excellence Award

  The Environmental Protection Agency has announced the winners of the 2019 Clean Air Excellence Awards. The awardee for the Transportation Efficiency category is RideFinders, a division of the GRTC Transit System, for their Commute Green Summer Challenge in Richmond, Va. The project involved a transportation demand management campaign to reduce the number of single-passenger commute trips and reduce vehicle emissions. Using existing resources, the project documented the emissions reductions, reduced vehicle miles traveled, and fuel savings. Other award categories are clean air technology, community action, education and outreach, state/tribal/local air quality policy, and an outstanding achievement award. For more information, link to the announcement. (11-8-19)

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• Nominations Sought for Alternative Fuel Corridor Designations

  The Federal Highway Administration is seeking nominations for the fourth round of its Alternative Fuel Corridors designations. This fourth round of corridor designations may provide state or local agencies an opportunity to nominate additional corridors, extend currently designated corridors, and/or nominate a different fuel(s) along an already designated corridor. Nominations are due Feb. 26. For more information, link to the announcement and the Alternative Fuel Corridors web page. (10-28-19)

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• CMAQ Emissions Tool Updated for Diesel Trucks/Engine Emissions

  The Federal Highway Administration has released a new module of the Congestion Mitigation and Air Quality (CMAQ) Emissions Calculator Toolkit. The Advanced Diesel Truck and Engine Technologies tool is one of a series of spreadsheet-based tools that can be used to facilitate the calculation of representative air quality benefit data, for CMAQ project justification, and annual reporting. The new module estimates emission reductions from projects that implement diesel retrofitting, diesel repowering, and diesel vehicle replacement. For more information, link to the toolkit. (9-30-19)

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• EPA, DOT Announce Federal Preemption Rule on Fuel Economy, GHG Emissions

  Federal environmental and transportation agencies have issued the One National Program Rule to provide for nationwide fuel economy and greenhouse gas (GHG) standards for automobiles and light trucks. The rule specifies that only the federal government may set fuel economy standards, and state and local governments may not establish their own separate standards. This includes state laws that substantially affect fuel economy standards (such as tailpipe GHG emissions standards and zero emission vehicle (ZEV) mandates). In addition, EPA is withdrawing the 2013 Clean Air Act waiver that authorized California to pursue its own tailpipe GHG standard and ZEV mandate. The agencies anticipate issuing a final rule on standards in the near future. For more information, link to the final rule web page. (9-19-19)

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• FHWA Provides Tool, Best Practices for Dust Mitigation

  The Federal Highway Administration has provided a tool to help practitioners calculate emissions from road dust. The dust mitigation tool and associated dust mitigation practices and model documentation were posted as part of FHWA’s Congestion Mitigation and Air Quality Improvement Program (CMAQ) Emissions Calculator Toolkit. The tool allows users to calculate emissions benefits from three different categories of dust mitigation projects: paved roads, unpaved roads, and unpaved to paved roads. The agency also has provided updates to the CMAQ tool for congestion reduction and traffic flow improvements. For more information, link to the toolkit. (8-24-19)

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• GAO Report Evaluates Federal Agency Use of Alternative Fuel Vehicles

  The Government Accountability Office has issued a report on the extent to which federal agencies are using alternative fuel vehicles in their fleets. The report says that federal agency use of alternative fuel vehicles has increased since they were first required to do so in 1988, but that a majority of the fleets are still powered by petroleum. The report also says that of the alternative fuel vehicles in the fleets, most are flex-fuel vehicles that run on gasoline-ethanol blends, with hybrids representing about 11% of federal alternative fuel vehicles and electric vehicles representing less than 1%. The report says that the higher cost of electric vehicles is a factor that keeps agencies from adding more of them to their fleets. For more information, link to the report. (8-26-19)

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• FHWA Publishes Ozone Nonattainment Area Maps

  The Federal Highway Administration has published maps of nonattainment areas for the 2015 eight-hour ozone national ambient air quality standards (NAAQS). Each map is intended to depict the boundaries of the designated area, including the boundaries of associated 2015, 2008, and 1997 eight-hour ozone nonattainment and/or maintenance areas (if any), as well as any associated MPOs. The maps are made available to help state DOTs and MPOs identify and understand the boundaries of nonattainment areas and how they intersect with other jurisdictional boundaries when complying with transportation conformity requirements of the Clean Air Act. For more information, link to the maps. (8-19-19)

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• Group Urges Congestion Pricing in Cities

  A report from the National League of Cities encourages cities to consider congestion charging systems as a solution to build communities, calm traffic, and improve quality of life for residents. Congestion pricing is a type of road user charge system in which a flat or variable rate fee is charged to vehicles that drive in a specified area or zone within a city. The report explains how congestion charging works, reviews pilot programs, and shows the potential advantages and barriers to implementation. For more information, link to the report. (8-19-19)

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• EPA Announces Latest Version of Calif. Emissions Model

  The Environmental Protection Agency has announced the availability of the latest version of the California Emission Factor model (EMFAC2017) for use in state implementation plan development and transportation conformity hot-spot analyses. The model is required for all new regional emission analyses that are started after Aug. 16, 2021, and for all new hot-spot analyses for carbon monoxide and particulate matter conducted on or after Aug. 17, 2020. For more information, link to the notice. (8-15-19)

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• Researchers Develop Simplified Tool to Calculate Emission Reductions under CMAQ

  A spreadsheet-based tool to calculate emission reductions for projects under the Congestion Mitigation and Air Quality Improvement (CMAQ) program has been developed under the National Cooperative Highway Research Program (NCHRP 25-25, Task 108). To obtain CMAQ funds, states must submit an analysis describing the air quality improvement benefits that the project or program will achieve. The research provides a method to calculate emissions reductions for 16 project types, based on minimized and simplified inputs. For more information, link to the report and related resources. (7-30-19)

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• EPA Outlines Achievements of Diesel Emissions Reduction Act

  The Environmental Protection Agency has issued a report to Congress providing an overview of the Diesel Emissions Reduction Act program, from its inception in 2008 through 2016. EPA awarded $629 million to retrofit or replace 67,300 engines in vehicles, vessels, locomotives or other pieces of equipment, with $300 million of this funding coming from the American Recovery and Investment Act. EPA estimates that these projects will reduce emissions by 472,700 tons of NOx and 15,490 tons of PM-2.5 over the lifetime of the affected engines. For more information, link to the report. (7-25-19)

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• EPA Proposes Revised Rule for Sources of Hazardous Air Emissions

  The Environmental Protection Agency has announced a proposed rule to establish requirements for sources of hazardous air pollutants that choose to reduce emissions and be reclassified. The rule would reverse the agency’s policy known as “once-in, always in” regarding toxic air emissions. That policy says industrial sources of toxic air pollution subject to strict “major” source air toxics controls must always meet those limits, even if they reduce emissions below the Clean Air Act’s threshold. The proposal would revise what qualifies as a major source and an area source of hazardous air pollutants. The EPA is expected to publish the rule in an upcoming Federal Register. For more information, link to the EPA web page. (6-25-19)

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• FHWA Posts Resources on Alternative Fuel Corridors

  The Federal Highway Administration has posted several new resources as part of its Alternative Fuel Toolkit. Recently posted items include tools for alternative fuel corridor planning as well as information related to convenings on the South Central, Southeast, and Midwest Alternative Fuel Corridors. For more information, link to the Alternative Fuel Toolkit. (6-13-19) >>See Related AASHTO CEE Resources: AASHTO Air Quality Community of Practice

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• NCHRP Issues Guide on Enhanced Truck Data for Emissions Modeling

  A guide for improving the modeling of commercial truck activity for estimating vehicle emissions from transportation projects is part of a set of resources issued under the National Cooperative Highway Research Program. The guide, NCHRP Research Report 909: Guide to Truck Activity Data for Emissions Modeling, provides a detailed discussion of the methods, procedures, and sources of data that can be used to enhance the truck-specific emissions estimates from the EPA’s Motor Vehicle Emissions Simulator (MOVES2014) model. The project also includes a web-only set of case studies and a collection of MS Excel files that contain data described in the case studies. For more information, link to the NCHRP Research Report 909. (6-12-19) >>See Related AASHTO CEE Resources: AASHTO Air Quality Community of Practice

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• EPA Awards Over $13 Million for Cleaner School Buses, Diesel

  The Environmental Protection Agency has announced awards totaling over $9.3 million to 43 states or territories to purchase hundreds of cleaner school buses. The grants under the EPA’s Diesel Emissions Reduction Act (DERA) funding will allow state, regional, or tribal governments and organizations to purchase buses that use newer, lower emission diesel buses to reduce pollution and improve public health. The EPA also has announced $3.8 million in DERA grants awarded to various groups in Alaska and the Pacific Northwest for the purchase of hybrid electric or cleaner diesel generators, construction equipment, transit buses, short-haul freight trucks, and school buses. For more information, link to the Region 10 and national announcements. (5-2-19)

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• FHWA Newsletter Provides Air Quality, Climate Updates

  Recent developments concerning air quality and climate impacts are presented in the recent issue of the Air Quality and Climate Change Highlights newsletter from the Federal Highway Administration. Topics covered include CMAQ computation guidance, alternative fuel corridor nominations, and renewable energy in rights-of-way. The newsletter also spotlights various meetings, conferences, symposia, workshops, and training opportunities. For more information, read the January/February 2019 issue. (4-4-19)

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• WRI Issues Costs and Emissions Appraisal Tool for Transit Buses

  The World Resources Institute has created a Costs and Emissions Appraisal Tool for Transit Buses. The Excel-based tool allows users to compare the costs and emissions reductions of two bus fleets, each composed of up to three bus types. Bus types can differ in terms of fuel type, the technology used to achieve different emissions standards, and bus length. Users can input fuel and vehicle unit cost data for a city or country and the tool calculates the costs and emissions of each bus type and the total costs and emissions of each fleet. To access the tool and a related discussion paper, link here. (March 2019)

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• Report Issued on Global Health Impacts of Transportation Pollution

  A review of transportation-related air pollution across the globe has been issued by the International Council on Clean Transportation. The transportation sector produces multiple pollutants such as dust and other airborne particles, ozone, and nitrogen dioxide from vehicle exhaust, vapor from fuels, and dust from unpaved roads, tire wear, and brake wear. The analysis provides updated estimates of the impacts of transportation sector emissions and their health impacts in 2010 and 2015 by linking state-of-the-art models on vehicle emissions, air pollution, and epidemiological analysis to determine the impact on air quality and public health. The report found that 84 percent of global transportation-attributable deaths occurred in G20 countries, and 70 percent occurred in the four largest vehicle markets: China, India, the European Union, and the United States. For more information, link to the report. (3-11-19)

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• EPA Extends Deadline for Clean Diesel Grants

  The Environmental Protection Agency has extended the deadline to apply for competitive grant funding through its Diesel Emissions Reductions Act Clean Diesel Funding Assistance Program. The program is soliciting applications for projects that achieve significant reductions in diesel emissions in terms of tons of pollution produced and exposure, particularly from fleets operating in areas designated as having poor air quality. Applications are due March 26. For more information, link to the extension notice. (2-21-19)

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• CMAQ Guidance Issued on Total Emissions Reduction Measure

  Guidance on calculating the total emissions reduction measure to assess on-road mobile source emissions under the Congestion Mitigation and Air Quality Improvement (CMAQ) program has been issued by the Federal Highway Administration. The measure is the 2-year and 4-year cumulative reported emission reductions, for all projects funded by CMAQ funds, by applicable criteria pollutant and precursors for which the area is designated nonattainment or maintenance. The guidance provides a calculation formula as well as frequently asked questions. For more information, link to the guidance. (December 2018)

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• DOE Launches Web Version of Fleet Life Cycle Tool

  The Department of Energy’s Argonne National Laboratory has announced a new online version of a tool to compare alternative fuel and vehicle technologies. Alternative Fuel Life-Cycle Environmental and Economic Transportation (AFLEET) is a free, publicly available spreadsheet-based tool to help fleet managers optimize their purchasing decisions to reduce their environmental impacts and save money. AFLEET was originally launched in 2013 and is now issued as a web-based option. For more information, link to the AFLEET tool. (2-1-19)

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• Bike, Pedestrian Module for CMAQ Emissions Calculator Toolkit Released

  The Federal Highway Administration has released a new module of the Congestion Mitigation and Air Quality (CMAQ) Emissions Calculator Toolkit. The Bicycle and Pedestrian Improvements module is one of a series of spreadsheet-based tools that can be used to facilitate the calculation of representative air quality benefit data, for CMAQ project justification, as well as the annual reporting requirements. The update includes a user guide and supplemental documentation. The toolkit is a resource to help with the implementation of the CMAQ program, which supports surface transportation projects and related efforts that contribute to improved air quality and reduce congestion. To access this and other modules, link to the toolkit. (1-24-19)

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• Diesel Idle Module for CMAQ Emissions Calculator Toolkit Released

  The Federal Highway Administration has released a new module of the Congestion Mitigation and Air Quality (CMAQ) Emissions Calculator Toolkit. The Diesel Idle Reduction Technologies tool is one of a series of spreadsheet-based tools that can be used to facilitate the calculation of representative air quality benefit data, for CMAQ project justification, as well as the annual reporting requirements. The toolkit is a resource to help with the implementation of the CMAQ program, which supports surface transportation projects and related efforts that contribute to improved air quality and reduce congestion. Additional toolkit modules are released as they become available. For more information, link to the toolkit. (1-3-19)

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• Smart Transportation Systems Can Improve Truck Environmental Impacts

  The National Center for Sustainable Transportation has issued a research study of the potential for using intelligent transportation system (ITS) technologies that take into account the presence of trucks in the traffic flow in order to reduce fuel consumption and pollution levels in areas of high truck volume. According to the study, the sizes and movement dynamics of trucks create traffic disturbances that affect other vehicles and cause increased fuel consumption and pollution. The study proposes an integrated variable speed limit, ramp metering, and lane change controller using feedback linearization. The integrated controller keeps the bottleneck flow at the maximum level and homogenizes the density and speed of the traffic flow along the highway sections. Results show improvements in fuel economy and emissions under different levels of perturbation and noise. For more information, link to the report. (2018)

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