<p>Only a small share of Americans choose sustainable modes for everyday transportation. Expanding the use of these modes has proven exceptionally challenging given the stickiness of car dependence. We develop a conceptual framework linking childhood transportation experiences with adults’ transportation choices, for themselves and for their children. We estimate binary logistic models to test these relationships, drawing on an original survey with a representative sample of the U.S. urban and suburban population (<i>N</i> = 2,155). Our results show that commuting to school exclusively via sustainable modes as a child—including school bus, walking, biking, and transit—reduces the probability of car dependence in adulthood (defined as using a car for 95% of trips, or more) by over 12% points, while being driven at least sometimes increases it by a similar margin. Moreover, we find a strong effect of parents’ early exposure to sustainable transportation—it is linked to a 31-percentage point rise in the probability that their children use sustainable modes to school—despite a small sub-sample of parents with children in the age group we considered (5th–8th graders). Early experiences with sustainable transportation emerge as formative, capable of driving sustainable transportation behaviors across generations. Yet, we estimate that for sustainable school travel experiences to reduce car dependence in the U.S., more than 60% of children would need to use the school bus or active modes like walking or biking to get to school.</p>