Aruna Sivakumar
CE 394K.3: GIS in Water Resources
Term Project Proposal
Implementing Soak-Time Distribution Models in a GIS Framework
Background: "The soak-time of vehicle trip starts is defined as the duration of time in which the vehicle's engine is not operating and that precedes a successful vehicle start" [Nair, Bhat & Kelly (2000)]. Area-wide mobile source emissions can be determined by estimating the temporal soak-time distribution in the area. This is an important step towards assessment of air quality and the battle against non-attainment. Nair, Bhat and Kelly have developed a model that predicts the zone-specific soak-time distributions for each combination of time-of-day and activity purpose. Given the zone-to-zone production-attraction matrices by trip purpose, we can obtain the number of trip starts by the zone of origin, activity purpose prior to trip start, and time-of-day (by applying fixed factors obtained from travel surveys). This can then be used to compute the zone-specific soak-time distributions.
Objective: To implement the soak-time distribution models in a GIS framework so that clicking on a particular zone will compute and display the soak-time distributions by time-of-day and activity purpose. This data will then serve as input to emission factor models (such as MOBILE6).
Scope: The models will be applied to the Dallas-Fort Worth region at the TAZ (Traffic Analysis Zone) level. The implementation is performed in TransCAD.
References:
http://www.epa.gov/otaq/m6.htm
http://www.epa.gov/oms/models.htm