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| Joint Center for Transportation & Air Quality |
| Project Title: | Development of High Speed Vehicle Emission Rates |
| Organization: | Texas Transportation Institute |
| Investigators: | Joe Zietsman, Dennis Perkinson, Brian Bochner |
At present, motor vehicle emission rates used for analyzing on-road emissions impacts are available in EPA's MOBILE6 model only for speeds of 65 mph and below. This limits the ability of analysts to assess the implications of actions that affect vehicles operating at speeds above 65 mph. Previously this might not have been a major shortcoming of the modeling. However, average travel speeds, especially in off-peak conditions, have increased on freeways and tollways to 75 to 80 mph in many areas. This is due to increased speed limits in many areas and limited speed limit enforcement. However, another new high speed condition is being planned in Texas — the high speed Trans Texas Corridor (TTC). State DOT engineers are currently working on design criteria for speeds up to 100 mph. Some corridors of this proposed 3,800 mile system are proposed to be located in or immediately adjacent to existing air quality nonattainment areas.
- The project will develop high speed motor vehicle emission rates for use in future emissions estimation to assess the impacts of changes to the roadway transportation system and related on-road emissions reduction measures. This will enable transportation and air quality planners to more reliably assess impacts associated with high speed operation already existing on freeways and tollways as well as future facilities that will start to appear in metropolitan transportation plans (MTPs) in the near future, at least in Texas.
- The project will generate actual emissions data obtained through portable emissions measurement system (PEMS) equipment mounted on vehicles driven through EPA driving cycles to be developed jointly with EPA. The data will then be applied to extend emission rate curves for many or all EPA vehicle classifications so they cover the full range of speeds up to 90 mph.
The project will be performed with close review and input by EPA so the results are deemed usable for emissions analyses and also can be used in future versions of EPA's emissions estimation models. A case study will also be prepared to demonstrate the differences in emissions analysis results that occur when the full speed range is available, both with and without TTC facilities. Results will be documented in task memoranda, a final project report, and a PowerPoint presentation for communication to interested audiences.
Technical Memorandum & Video
Drive Cycle Development for Determining High Speed Emission Rates ( 295 KB)
High speed drive cycles were developed for the purpose of testing high speed operations of heavy duty and light duty test vehicles.
Heavy-Duty Diesel Vehicle Test ( )
The above movie clip shows highlights of a TTI test on a heavy-duty diesel vehicle as part of their High Speed Emissions Testing Project.
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| Page Updated/Reviewed: 05/09/2007 2:59 PM |
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