TRB 2016 Blue Ribbon Committee
16th National Transportation Planning Applications Conference

Modeling Impacts Of Autonomous Vehicles On Travel Demand With An Activity-Based Model

Corresponding Author: Peter Vovsha, WSP

Presented By: Peter Vovsha, WSP


The paper describes an approach to model future scenarios with a substantial penetration of Autonomous Vehicles (AVs). The recently developed Activity-Based Model (ABM) for the Phoenix, AZ region was used as the platform. Impacts of AVs and corresponding modifications of ABM can be classified as follows:

(1) Elderly, youth, disable, and other people without a driver license will have access to cars; consequently, auto driver mode availability was not constrained by age of 16 as in standard applications but extended to 12.

(2) Cars become available at any location any time, and not necessarily from home for the entire tour; to address this, the mode choice rules were relaxed to allow for any sequence of auto, transit, and non-motorized trips on the same tour.

(3) Empty repositioning trips made by AVs (primarily to and from home) were considered as a way to facilitate intra-household sharing of cars; to model this effect, certain travel tours were probabilistically chosen (based on the number of stops and main activity duration) to have car repositioning trips to and from home in the middle of the tour.

(4) General convenience of AV as an access mode to transit; AV provides essentially a new mode of transportation that combined advantages of Park-and-Ride (PNR) and Kiss-and-Ride (KNR) modes. It is as convenient as PNR in terms of an independency for each person and it is as convenient as KNR in terms of a free choice of any station where drop-off or pick-up can take place. To accommodate this new mode, its utility was constructed with convenience parameters equalized to auto and actual level-of-service characteristics.

(5) In-Vehicle Time Productivity; AVs offer a significant advantage over conventional vehicles in terms of productivity (working, reading, texting, etc). To address this aspect, the in-vehicle time coefficient for AVs was tested with a productivity “bonus” pertinent to premium transit.

(6) Optimized use of highway capacity, efficient driving and increased intersection capacity; to address this effect in traffic assignments link capacities were tested with various improvement assumptions.

The paper describes the results and corresponding impacts of AVs on mode choice and traffic assignment.


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