Date of Award

5-2023

Document Type

Dissertation

Degree Name

Doctor of Philosophy (PhD)

Department

Civil Engineering

Committee Chair/Advisor

Dr. Jennifer Ogle

Committee Member

Dr. Ronnie Chowdhury

Committee Member

Dr. Wayne Sarasua

Committee Member

Dr. Patrick Gerard

Committee Member

Dr. Andrew Robb

Abstract

This dissertation focuses on the challenge of pedestrian interaction with autonomous vehicles (AVs) at unmarked midblock locations where the right-of-way is unspecified. A virtual reality (VR) simulation was developed to replicate an urban unmarked midblock environment where pedestrians cross a four-lane arterial roadway and interact with AVs. One research goal is to investigate the impact of roadway centerline features (undivided, two-way left-turn lane, and median) and AV operational schemes portrayed through on-vehicle signals (no signal, yellow negotiating indication, and yellow/blue negotiating/no-yield indications) on pedestrian crossing behavior. Results demonstrate that both roadway centerline design features and AV operations and signaling show significant impacts on pedestrians' unmarked midblock crossing behavior, including the waiting time at the curb, waiting time in the middle of the road, and the total crossing time. Whereas, only the roadway centerline design features significantly impact the walking time, and only the AV operations and signaling significantly impact the accepted gap. Participants in the undivided centerline scene spent longer time waiting at the curb and walking on the road. Also, pedestrians are more likely to display risky behavior and cross in front of AVs indicating blue signals with non-yielding behavior in the presence of a median centerline scene. The inclusion of a yellow signal, which indicates the detection of pedestrians and signifies that the AVs will negotiate with them, resulted in a significant reduction in pedestrian waiting time both at the curb and in the middle of the road, when compared to AVs without a signal. Interaction effects between roadway centerline design features and AV operations and signaling are significant only for waiting time in the middle of the road. It is also found that older pedestrians tend to wait longer at the curb and are less likely to cross in front of AVs showing a blue signal with non-yielding behavior. Another research goal is to investigate how this VR experience change pedestrians’ perception of AVs. Results demonstrated that both pedestrians’ overall attitude toward AVs and trust in the effectiveness of AV systems significantly improved after the VR experience. It is also found that the more pedestrians trust the yellow signals, the more likely they are to improve their perception of AVs. Further, pedestrians who exhibit more aggressive crossing behavior are less likely to change their perception towards AVs as compared to those pedestrians who display rule-conforming crossing behaviors. Also, if the experiment made pedestrians feel motion sick, they were less likely to experience increased trust in the AV system's effectiveness.

Author ORCID Identifier

0000-0002-1857-8826

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