Factors related to rapid deceleration events among a large cohort of older drivers David W. Eby a,b,⇑ , Lisa J. Molnar a,b , Jennifer S. Zakrajsek a,b , Lindsay H. Ryan c , Nicole Zanier a,b , Renée M. St. Louis a,b,d , Sergiu C. Stanciu a,b , David LeBlanc a , Scott Bogard a , Lidia P. Kostyniuk a,b , Jacqui Smith c , Raymond Yung e , Linda Nyquist e , Marian E. Betz f , Carolyn DiGuiseppi g , Vanya Jones h , Guohua Li i,j , Thelma J. Mielenz i , David Strogatz k , on behalf of the AAA LongROAD Research Team 1 a University of Michigan Transportation Research Institute, Ann Arbor, MI, USA b Center for Advancing Transportation Leadership and Safety (ATLAS Center), Ann Arbor, MI, USA c Institute for Social Research, University of Michigan, Ann Arbor, MI, USA d Monash University Accident Research Centre, Clayton, Victoria, Australia e Institute of Gerontology, Division of Geriatric and Palliative Medicine, University of Michigan, Ann Arbor, MI, USA f Department of Emergency Medicine, University of Colorado School of Medicine, Aurora, CO, USA g Department of Epidemiology, Colorado School of Public Health, University of Colorado Anschutz Medical Campus, Aurora, CO, USA h Department of Health, Behavior and Society, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, USA i Department of Anesthesiology, Columbia University College of Physicians and Surgeons, New York, NY, USA j Department of Epidemiology, Mailman School of Public Health, Columbia’s Injury Control Research Center, Columbia University, New York, NY, USA k Bassett Research Institute, Bassett Healthcare Network, Cooperstown, NY, USA article info Article history: Received 15 February 2019 Received in revised form 15 July 2019 Accepted 25 August 2019 Keywords: Aging Traffic safety Driving behavior Hard braking abstract Studies over the past two decades have attempted to document and understand factors related to crashes involving older drivers to develop more effective countermeasures to reduce the frequency and severity of these crashes. Studies in which vehicle acceleration data can be recorded have begun to explore the relationship between rapid deceleration events (RDEs) and functional abilities among older drivers as a surrogate measure of unsafe driving. Recent naturalistic driving studies with older adults have found differing results using different thresholds to define an RDE. The present study examined the relationship among RDE rates, demographics, visual abilities, cognitive abilities, and driving comfort among a large cohort of older drivers, using two definitions of RDEs—longitudinal deceler- ation of 0.35 g or greater (RDE35) and longitudinal deceleration of 0.75 g or greater (RDE75). The study utilized objective driving, objective functioning, and reported driving comfort data from 2774 participants of the multi-site AAA Longitudinal Research on Aging Drivers (LongROAD) study. RDE rates for each threshold were calculated per 1000 miles driven. Multivariate regression models with backward elimination were developed to examine how outcome measures were related to RDE rates. Too few RDE75 events were found for meaningful analysis. RDE35 rates were significantly associated with several https://doi.org/10.1016/j.trf.2019.08.021 1369-8478/Ó 2019 Elsevier Ltd. All rights reserved. ⇑ Corresponding author at: University of Michigan Transportation Research Institute, 2901 Baxter Rd., Ann Arbor, MI, 48109, USA. E-mail address: eby@umich.edu (D.W. Eby). 1 Howard Andrews and Linda Hill. Transportation Research Part F 66 (2019) 76–86 Contents lists available at ScienceDirect Transportation Research Part F journal homepage: www.elsevier.com/locate/trf