Effects of transit bus interior configuration on performance of wheeled mobility users during simulated boarding and disembarking Clive D'Souza, Ph.D. a, * , Victor Paquet, Sc.D. b, c , James A. Lenker, Ph.D. b, d , Edward Steinfeld, Arch.D. b, e a Center for Ergonomics, University of Michigan, Ann Arbor, MI, United States b Center for Inclusive Design and Environmental Access, University at Buffalo, NY, United States c Department of Industrial and Systems Engineering, University at Buffalo, Buffalo, NY, United States d Department of Rehabilitation Science, University at Buffalo, Buffalo, NY, United States e School of Architecture and Planning, University at Buffalo, Buffalo, NY, United States article info Article history: Received 6 October 2016 Received in revised form 9 February 2017 Accepted 13 February 2017 Keywords: Wheelchairs Accessibility Usability Low-floor bus Public transportation abstract The emergence of low-floor bus designs and related regulatory standards in the U.S. have resulted in substantial improvements in public transit accessibility. However, passengers using wheeled mobility devices still experience safety concerns and inefficiencies in boarding, disembarking, and interior cir- culation on low-floor buses. This study investigates effects of low-floor bus interior configuration and passenger crowding on boarding and disembarking efficiency and safety. Users of manual wheelchairs (n ¼ 18), powered wheelchairs (n ¼ 21) and electric scooters (n ¼ 9) simulated boarding and dis- embarking in three interior layout configurations at low and high passenger crowding conditions on a full-scale laboratory mock-up of a low-floor bus. Dependent measures comprised task times and critical incidents during access ramp use, fare payment, and movement to and from the doorway and wheeled mobility securement area. Individual times for unassisted boarding ranged from 15.2 to 245.3 s and for disembarking ranged from 9.1 to 164.6 s across layout and passenger crowding conditions. Nonpara- metric analysis of variance showed significant differences and interactions across vehicle design con- ditions, passenger load and mobility device type on user performance. The configuration having electronic on-board fare payment, rear-bus entrance doorways and adjacent device securement areas demonstrated greatest efficiency and safety. High passenger load adversely impacted efficiency and frequency of critical incidents during on-board circulation across all three layouts. Findings have broader implications for improving transit system efficiency and quality of service across the spectrum of transit users. © 2017 Elsevier Ltd. All rights reserved. 1. Introduction Public transit affects community participation in employment, recreation, and access to services such as education and healthcare. Increases in life span, improved medical care, and increasing availability of assistive technologies that promote independence have resulted in a growing need for accessible public transportation that provides efficient and safe services for those with disabilities, including users of wheeled mobility devices (WhMDs). The population of non-institutionalized WhMD users (i.e., those not in nursing homes or in hospitals) in the US is presently estimated at 3.4 million (Brault, 2012) and continues to grow at an annual rate of 5% (Flagg, 2009). Over 40% of WhMD users living in areas served by public transit experience significant environmental and design barriers when using public transit services (LaPlante and Kaye, 2010). Low-floor buses (LFBs) are currently the most common type of bus design used in urban public transit (NTD, 2012). Electrome- chanical ramps at the doorways eliminate horizontal gaps between the bus floor and sidewalks improving access for WhMD users (Cross, 2006; King, 1998). LFBs are preferred by many transit agencies because they contribute to shorter dwell times (i.e., the amount of time a bus is stopped at the curb while passengers board * Corresponding author. Center for Ergonomics, Department of Industrial and Operations Engineering, G636 IOE, University of Michigan, 1205 Beal Avenue, Ann Arbor, MI 48109-2117 USA. E-mail address: crdsouza@umich.edu (C. D'Souza). Contents lists available at ScienceDirect Applied Ergonomics journal homepage: www.elsevier.com/locate/apergo http://dx.doi.org/10.1016/j.apergo.2017.02.008 0003-6870/© 2017 Elsevier Ltd. All rights reserved. Applied Ergonomics 62 (2017) 94e106