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Model Report


Last Revision Date: 03/31/2011 View as PDF
General Information Back to Top
Model Abbreviated Name:

Model Extended Name:

Model Overview/Abstract:
A working research model for Atlanta, GA has been developed by Georgia Tech, and is called the Mobile Emissions Assessment System for Urban and Regional Evaluation (MEASURE). The EPA Office of Research and Development has developed an additional implementation of the MEASURE research model for the Research Triangle Park, NC area. The MEASURE emissions modeling concept will benefit state and local air quality agencies, local metropolitan planning organizations, or academic research organizations to further their understanding of current transportation emissions sources as well as to model future transportation control strategies. At present, MEASURE focuses on estimating emissions for ozone precursor pollutants (volatile organic compounds, nitrogen oxides, carbon monoxide) and has limited emission estimation capabilities for other pollutants. In the future, better characterization of particulate matter and hazardous air pollutant (air toxic) emissions is planned.

MEASURE includes the following advancements to the state-of-the-art highway vehicle emissions modeling:

  • Advanced modeling of emissions rate characteristics of different vehicle technology groups;
  • Advanced modeling of vehicles based on power demand characteristics;
  • Advanced modeling of vehicles as a function of a vehicle's mode of operation;
  • Characterization of physical transportation networks in terms of spatially distributed attributes (e.g., road grade) that affect vehicle modal operations; and
  • Integration of model development and application in a GIS environment, linking spatially arrayed vehicle distribution, vehicle usage, and behavior, and transportation network characteristics and volume flows.
The basis for this model is modal, which refers to the modes of engine operation that a vehicle may be in at any given point in time such as engine start, idle, hot stabilized operation, enrichment conditions (influenced by high acceleration and power demand), hot soak evaporation, etc. Within the current model design, a variety of vehicle activities, environmental factors, vehicle and driver characteristics are considered as well as the spatial and temporal distributions of these vehicle and driver characteristics.

On- and off-network components are included in the model. On-network components refer to vehicle activity on major roadway links such as interstates, major arterials, etc. Traffic volumes, speeds, temporal distributions, and fleet characteristics are included for network components. Off-network components refer to vehicle activity on local roads and streets. Typically, these local roads are aggregated into mini-transportation analysis zones. Off-network activities are derived from socioeconomic and environmental data (i.e., population, housing, employment, land use) and aggregated on a zone basis.

Fleet composition is an important factor in the model. This is due to the numerous vehicle parameters that are used to determine emission rates. These vehicle parameters include vehicle class, emitter class, model year, gross vehicle weight, engine displacement, and fuel injection and control system technology. Additionally, these vehicles have spatial variations throughout an urban area with correlations to certain socio-economic data (e.g., population, housing income). The fleet for a given area is subdivided into various technology groups and these groups are tracked within the model. Emission rates are applied separately to each technology group. The emission rate algorithms included in the model are based upon statistical analysis of emissions data and will be determined for all the modes that are included in the model.

Model Technical Contact Information:
Sue Kimbrough
Office of Research and Development (ORD)
National Risk Management Research Laboratory (NRMRL)
Atmospheric Pollution Prevention & Control Division (APPCD)
U.S.EPA/NRMRL (Mail Code: MD-E305-02)

MEASURE was developed by the Georgia Institute of Technology through a cooperative research agreement with US EPA Office of Research and Development. Georgia Tech contacts:

  • Mike Rodgers

  • Randy Guensler
Model Homepage: http://www.epa.gov/nrmrl/appcd/mmd/mobile.html

User Information Back to Top
Technical Requirements
Computer Hardware
Compatible Operating Systems
Unix/Sun Solaris 2.7 or higher
Other Software Required to Run the Model
For the sake of brevity, the minimum hardware/software requirements at this time are: Sun Ultra 10, Solaris 2.7, 9 GB hard drive, ARC/Info(C) 8.0.2, ARC Network, and ARC Grid. This would be a minimum configuration to run the model on a Unix platform. However, it is possible to view the output files using ArcView(C). This is also an ESRI product and will run on a variety of platforms including personal computers (PCs). In this case, an end user would at a minimum require a Pentium class PC with a 400 Mhz CPU, color monitor, 10 GB harddrive, Microsoft(C) Windows2000(C), ArcView(C) 3.2 (or higher), and Microsoft(C) Access(C) or similar database engine.
Using the Model
Basic Model Inputs
Complex model with substantial input requirements and/or substantial modular or sub-model components.
Basic Model Outputs
Emissions on a road link basis.
User Support
User Qualifications
User needs only moderate level of technical education and/or modeling experience. To create and manage input data, user must be skilled in use of Arc/INFO. To view model outputs, a lesser skill level, i.e., ArcView is required.

Model Science Back to Top
Summary of Model Structure and Methods
The basis for this model is modal -- modal refers to the modes of engine operation that a vehicle may be in at any given point in time. (A conceptual overview of the model is presented in Figure 1.) Engine starts, idle, hot-stabilized operation, enrichment conditions (caused by power demand), and hot soak evaporation just to name a few are important vehicle operating modes. Emission rates are applied to the various vehicle modes of operation to obtain a set of modal emissions. Within the current model design, a variety of vehicle activities, environmental factors, and vehicle and driver characteristics are considered as well as spatial and temporal distributions.

The model uses mixed U.S. and S.I. units.

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