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29 SEP 2023 (TUE) | 10:00 – 11:00

Using AVs to Replace Buses & Complement Urban Rail Systems

SPEAKER Professor Kara Kockelman Dewitt Greer Centennial Professor of Transportation Engineering Department of Civil, Architectural and Environmental Engineering The University of Texas at Austin DATE AND TIME September 29 (Friday) 10:00 – 11:00 am (Hong Kong Time) REGISTRATION Please register by using this link: Confirmation emails with ZOOM link will be sent to participants before the lecture. This Distinguished Transport Lecture will be held on ZOOM only. ORGANISED BY Institute of Transport Studies, The University of Hong Kong ABSTRACT Motivated by shared autonomous vehicles’ (SAVs’) many potential services (like door-to-door [D2D] service, first-mile last-mile [FMLM] service, and bus replacements), this work explores traveler choices for different US settings, simulates fleets of SAVs in concert with other fixed-route transit, and analyzes results for travelers, their networks, and their regions. The presentation first microsimulates how SAVs can provide FMLM service to (and from) 5 commuter rail stations in central Austin neighborhoods. With train headways of 15 minutes, simulations predict dramatic increases in train use (by roughly a factor of 10, at those stations). Variations in train headways and SAV fleet sizes illustrate how D2D travel remains the key predictor of mode choice. Four-seat SAVs perform similarly to 6-seat SAVs, but cost less to provide. A dynamic ride-sharing (DRS) (vehicle-to-passenger assignment) algorithm tightly coordinated with train arrivals delivers 87% of travelers to their stations in time to catch the next train, while uncoordinated assignments deliver just 57% in time. Second, this work simulates 10-seat SAVs providing fixed-route transit service alongside private automobiles. System costs for each traveler type along a 6.4-kilometer (4-mile) corridor are computed across different SAV-use rates. The work prices out walking, waiting, riding, and driving times for all travelers in the corridor, along with vehicle ownership, parking, and operating costs. Results suggest that such self-driving mini-buses or 10-seat SAVs lower total costs per passenger-kilometer traveled when SAV mode split exceeds 30 percent, even though walking and waiting are valued at a relatively high cost. Third, a POLARIS-based mesoscopic simulation integrates three SAV service types across the 20-county Chicago region. When SAVs with DRS serve only D2D trips, at just $0.50 per passenger-mile, with 1 SAV for every 40 residents, they attract 15% of trips (and private vehicle ownership falls from 0.66 to 0.37 cars per capita), with a 15-minute average travel time and 4.6-mile average person-trip distance. Adding FMLM service (to about 54,000 train and bus stops) increases the region’s transit split: from 5.4% to 6.3% of travelers, with the same SAV fleet serving 12% more person-trip requests per day and driving 4.2% more SAV-miles. Most FMLM person-trip distances are under 2 miles, with rail-station connections dominating (rather than those to bus stations). Overall, many metro regions of the globe and their transit systems seem ready to benefit from SAV services. SPEAKER’S BIO Prof. Kara Kockelman is a registered professional engineer and holds a PhD, MS, and BS in civil engineering, a master’s in city planning, and a minor in economics from the University of California at Berkeley. She has been a professor of transportation engineering at the University of Texas at Austin for 25 years, and is the recipient of an NSF CAREER Award, Google Research Award, MIT Technology Review Top 100 Innovators Award, Vulog’s Top 20 of 2020 Influential Women in Mobility, and various ASCE, NARSC, TRF, and WTS awards. She recently served as President of the North American Regional Science Association and sits on the Eno Center for Transportation’s Advisory Board, as well as 3 TRB Committees. She has authored over 200 journal articles (and two books), and her primary research interests include planning for shared and autonomous vehicle systems, the statistical modeling of urban systems, energy and climate issues, the economic impacts of transport policy, and crash occurrence and consequences. Pre-prints of these articles (and book contents) can be found at She hopes you will join the zero-cost, zero-carbon Bridging Transportation Researchers conference (held in August each year), by submitting papers in spring & then registering here:

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