Mobile Sources

ERG is a national leader in clean and efficient transportation technologies, fuels, and operational solutions. We specialize in modeling mobile source emissions and developing inventories of criteria pollutants, particulate matter (including black carbon), toxics, and greenhouse gases, in the United States and abroad. Our experts have developed, managed, and evaluated a wide range of successful emission control initiatives, including local and state-level inspection and maintenance programs, accelerated vehicle retirement programs, green freight strategies, evaluations of retrofit programs for on- and off-road sources, and stakeholder outreach and engagement campaigns. We have pioneered real-world on-board testing of vehicle emissions and fuel efficiency, and used this information to develop complex algorithms for input into EPA and California Air Resources Board emissions models. ERG's studies have also provided data and analytical solutions supporting EPA vehicle miles per gallon (MPG) ratings. Our mobile source experts work closely with our economists, policy analysts, software engineers, communications specialists, database designers, and other professionals to deliver an outstanding suite of integrated services to our clients.

Data Collection and Analysis
  • Portable emission measurement systems
  • Portable activity monitoring system instrumentation
  • Remote sensing device (RSD) data collection
  • Fleet operations and vehicle activity surveys
  • Expert interviews
  • Statistical analysis of activity and emissions data
  • Marine Automatic Identification System (AIS) analysis
  • Matching of vessels to their characteristics (e.g., engine type, kilowatt rating of propulsion and auxiliary engines, vessel speed, and carrying capacity)
  • Development of geographic information system (GIS) shape files for shipping lanes, ports, rail segments, railway yards, and airports
  • Linking aircraft to engine characteristics
Modeling and Emission Factor Development
  • MOVES/EMFAC development and applications
  • NONROAD/OFFROAD modeling
  • Link-level emissions modeling
  • RSD program effectiveness
  • Statistical analysis of emission data
  • Development of region-specific railroad emissions models
  • EDMS/AEDT aviation modeling
Inspection/Maintenance Programs
  • I/M program design and evaluation
  • Inspection and repair cost-effectiveness
  • Compliance assessments
  • Enforcement audits
  • Acceptance testing
Control Strategy Evaluation
  • Engine modification and retrofit effectiveness
  • Advanced fuel efficiency technologies
  • Analysis of new and proposed emission and fuel economy standards
  • Green freight strategies
  • Alternative fuels analysis
  • RSD/on-board diagnostic implementation
Nonroad and Diesel Expertise
  • Heavy-duty off-road emission testing
  • Fleet-specific surveys and control evaluations
  • Nonroad controls/technology options
  • Specialized emission factors and modeling
Emission Inventory Development
  • National Emissions Inventory (NEI) support
  • State Implementation Plan/Transportation Conformity analysis support
  • Light- and heavy-duty on-road analysis
  • Nonroad equipment (construction, agricultural, other) analysis
  • Port emission inventory development
  • GREET marine vessel emission estimating tool support
  • Aircraft/airport, locomotive, and marine vessel  analysis
  • Criteria pollutants, particulate matter (PM), toxics, greenhouse gases (GHGs), black carbon
  • Trends forecasting
Economic and Regulatory Support
  • Controls/technology cost-effectiveness
  • Voluntary program assessments
  • Implementation and compliance evaluations
  • Financial impact assessments
  • I/M test fee evaluations
Mobile Source Software Products
  • Spatial Emissions Estimator (SEE) link-level emissions modeling utility
  • Freight shipper/carrier emission footprint and benchmarking tools
  • Vehicle Identification Number (VIN) decoder
  • High/low emitter profiles
  • Failure probability lookup utility
  • Customized nonroad modeling utility
  • Diesel engine retrofit calculator
  • Rail yard emission reduction estimating tools
Communications and Outreach
  • Stakeholder outreach and engagement
  • Voluntary and regulatory program support
  • Website development
  • Technical writing and editing
  • Traditional and social media, webinars, and marketing campaigns
  • Conference and event support


Service Area Leads

Rick Baker

The environmental issues we face today are complex and multi-faceted. Reducing emissions of greenhouse gases, ozone precursors, particulates, and other pollutants involves careful application of a variety of skill sets. Working at ERG allows me to collaborate with a wide range of national experts in environmental science, engineering, statistics, economic and policy analysis, IT, and communications in order to develop integrative solutions to these problems. The work challenges me to continually expand my abilities and my perspective.

Rick Baker

Richard Billings

These are exciting times. Rapid increases in computing power and greater availability of relevant data sets are making it possible to create systems that quantify emissions from aircraft, marine vessels, and railways. I am proud to be part of a team of experienced scientists and engineers at ERG with whom I can do high-quality work in this increasingly complex, challenging environment. By combining our perspectives and skill sets, we leverage these new opportunities and solve the problems inherent in handcrafting state-of-the-art air data sets.

Richard Billings

Tim DeFries

In my line of work, the data are often noisy and incomplete. Creativity, critical thinking, and precision are essential to avoid reaching incorrect conclusions—and that’s part of what I love about my work. I get to collaborate with great colleagues and clients in developing and rigorously implementing innovative solutions to provide credible results.

Tim DeFries

Sandeep Kishan

I have dedicated my career to reducing the energy and emission footprint of vehicle travel, a major source of air pollution worldwide. Thanks to inspiration from great mentors and clients, I had the opportunity to build and manage what has become a world-class team of mobile sources experts who relish the challenge of tackling complex problems. I am gratified beyond measure that our work has helped improve air quality, not only across the United States but also in other countries around the world, where we have facilitated development of customized solutions based on local conditions.

Sandeep Kishan

John Koupal

Thanks to a summer job at EPA—where I went into a frigid test cell in a parka at 5:00 each morning to prepare cars for emission testing—I became hooked on environmental work. After many years supporting EPA in developing several major air emission rules, I find it deeply gratifying to apply the knowledge I’ve acquired to help other countries take similar measures to achieve significant reductions in their pollution.

John Koupal

Jim Lindner

Throughout my career, first at EPA’s Office of Transportation and Air Quality and now with ERG’s mobile sources group, the best part of my work has been helping others—for example, by analyzing available data (which never seem to be ideal), explaining the results to technical and non-technical audiences in ways they can readily understand, and providing options for moving forward. It also seems to help if I try to listen more than I talk, not to take myself too seriously, and share a few laughs along the way.

Jim Lindner

Michael Sabisch

I feel incredibly fortunate to have a job where I can work with gifted colleagues on challenging projects supporting important efforts. The work is diverse and dynamic, and ERG gives our team the resources we need to be successful, as we try to leave the world a better place for future generations.

Michael Sabisch

Ian Todreas

Words are powerful. I learned this firsthand when, two decades ago, I picked up a magazine and found an article on climate change. I read it and everything changed. I am grateful to be at ERG, where I get to work on two things I care about deeply: clear, powerful communications and the environment.

Ian Todreas