A comparison of emissions estimated in the TRANSMIS approach with those estimated from continuous speeds and accelerations
TRANSIMS is a simulation system for the analysis of transportation options in metropolitan areas. Its major functional components are: (1) a population disaggregation module, (2) a travel planning module, (3) a regional microsimulation module, and (4) an environmental module. In addition to the major functional components, it includes a strong underpinning of simulation science and an analyst`s toolbox. The purpose of the environmental module is to translate traveler behavior into consequent air quality. The environmental module uses information from the TRANSIMS planner and the microsimulation and it supports the analyst`s toolbox. Transportation systems play a significant role in urban air quality, energy consumption and carbon-dioxide emissions. Recently, it has been found that current systems for estimating emissions of pollutants from transportation devices lead to significant inaccuracies. Most of the existing emission modules use very aggregate representations of traveler behavior and attempt to estimate emissions on typical driving cycles. However, recent data suggest that typical driving cycles produce relatively low emissions with most emissions coming from off-cycle driving, cold-starts, malfunctioning vehicles, and evaporative emissions. Furthermore, some portions of the off-cycle driving such as climbing steep grades are apt to be correlated with major meteorological features such as downslope winds. These linkages are important, but they are not systematically treated in the current modeling systems. The TRANSIMS system holds the promise of a more complete description of the role of heterogeneity in transportation in emission estimation. The TRANSIMS micro-simulation produces second by second vehicle positions defined by 7.5 meter cell locations. An approach has been used to convert average cell populations and average transitions between cells into fine-grained distributions of speeds and accelerations. This paper describes the approach and compares the emissions that result from: (1) actual measured trajectories, and (2) the TRANSIMS approach applied to cell positions extracted from the actual trajectories. Seven different levels of congestion of freeways are examined and three different groupings of arterials were analyzed.
- Research Organization:
- Los Alamos National Lab., Technology and Safety Assessment Div., NM (United States)
- Sponsoring Organization:
- Department of Defense, Washington, DC (United States); Department of Transportation, Washington, DC (United States); Environmental Protection Agency, Washington, DC (United States)
- DOE Contract Number:
- W-7405-ENG-36
- OSTI ID:
- 325769
- Report Number(s):
- LA-UR-98-3162; CONF-990112-; ON: DE99002063; TRN: AHC29910%%77
- Resource Relation:
- Conference: Transportation Research Board (TRB) annual meeting, Washington, DC (United States), Jan 1999; Other Information: PBD: [1998]
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
COMPUTERS
INFORMATION SCIENCE
MANAGEMENT
LAW
MISCELLANEOUS
32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATION
54 ENVIRONMENTAL SCIENCES
T CODES
URBAN AREAS
AIR QUALITY
PROBABILISTIC ESTIMATION
AIR POLLUTION
VEHICLES
ROAD TRANSPORT
ROUTING
ENERGY CONSUMPTION
EXHAUST GASES
COMPARATIVE EVALUATIONS