AASHTO CA02-5 examines trends in vehicle availability in the U.S. from 2000 to 2017; presents overall trends and with a focus on zero-vehicle households; and assesses the commute mode patterns of workers by their household automobile availability. The analysis draws on three different data sources comprised of multiple associated datasets - the Public Use Microdata Samples of the U.S. Census and the American Community Survey (ACS), and the National Household Travel Survey (NHTS).