Vehicle tracking (Household-level) design and scope

[joecastiglione]

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HH level implementation: where the vehicles owned / available to a HH are tracked in time and space based on the choices made by HH members

Revised Description:

The purpose of this task is to explicitly represent household vehicles in the ActivitySim modeling system. Representation of household vehicles means that each vehicle available to every household is explicitly identified and its location in time and space tracked, in a manner consistent with the household activity generation, mode choices, location choices and time-of-day choices. Explicit representation of household vehicles will improve the model system’s realism by reflecting logical real-world constraints and tradeoffs, improve the consistency and coherence of choices across model subcomponents and final outcomes, and improve and extend model system reporting. In addition, an explicit representation of household vehicle allocation and tracking will provide a foundation for subsequent efforts to represent and estimate the effects of future autonomous vehicles, although AVs will not be addressed as part of this scope.

It is expected that a significant share of all the existing model system components will be affected by the explicit representation of household vehicles, and the critical first step will be the preparation of a detailed design document to guide model system development. This design document will exhaustively review all model system components to identify where household vehicle availability in time and space as well as vehicle attributes will constrain or influence travel choices. Some of the choices “upstream” in the model system sequence may simply be influenced by vehicle availability such as at the joint activity generation level, while other choices further “downstream” in the model system may impose explicit constraints, such as on trip mode choice. For each model system component potentially affected by the explicit representation of household vehicle allocation, the design document will propose specific modifications to the model specifications and data structures. In coordination with the development of the design document, available household travel diary data will be reviewed to assess the completeness and sufficiency of this observed data to support subsequent model development. Critically, because of the potential broad extent of the models impacted by household vehicle tracking, and because many of these changes will involve both restructuring and re-estimating model system components and data structures, the design document will propose a phased multi-year implementation approach. In the initial phase to be performed as part of the ActivitySim Phase 6 scope, it is anticipated that household vehicles will be "loosely tracked", meaning that simple allocation methods will be implemented to track vehicles in time and space, but that the existing model component specifications and available alternative constraints will not be significantly modified and will not impose hard constraints. This effort may also be coordinated with other Phase 6 scope items, such as the vehicle type model development, and the improved escort model development.

[joecastiglione]

Agency Comments:

ODOT: can we link with item 32 (bring vehicle type modeling adjacent to this).

SFCTA: I can envision vehicle tracking (if at HH level) as tied models of vehicle allocation choice/priority and reflecting joint travel choices, but not necessarily tied to vehicle type, unless certain types of vehicles have constraints on distance, number of drivers+passengers, etc. The vehicle type modeling sounds like its more about propulsion technology, and perhaps operating costs

MTC: See comment for "Household vehicle types model".

SANDAG: For HH level implementation, the treatemetn of human driven vehicles and AVs are different; this covers both HVs and AVs? Also, is vehicle allocation/tracing in the demand model or in a post processing step after trip lists are generated? SANDAG has a simple AV allocation post processing procedure that allows tracing zombie AV VMT. B) for fleet level implementation, is it a TNC fleet allcocation/optimization procedure similar to Uber/Lyft routing algorithm? Is it in the demand modeling or in the post processing? SANDAG has a simple TNC routing procedrue as a post demand modeling step using a simplified rule-based Lyft Line algorithm.

Ohio: Note that this is not trivial.