Can information increase support for transportation reform? Results from an experiment

Can information increase public support for transportation reform? To understand the associations between knowledge, policy preferences, and information campaigns, we conducted a survey experiment of 597 U.S. adults, including an initial survey and a six-month follow-up. We focus on transportation policies that have high support for the status quo and whose corresponding essential facts are generally misunderstood: congestion relief (induced demand) and transportation finance (funding shortfall). We find that traffic dynamics are poorly understood, that misunderstandings are closely associated with preferences about congestion relief, and that exposure to information about induced demand meaningfully decreases support for road widening. The results differed for transportation finance: while providing information increased support for raising the gas tax, relevant knowledge was already widespread and was not closely associated with policy preferences. Providing information did not lead to long-lasting effects for congestion or finance. In both cases, support for reform reverted to initial levels after six months. Ultimately, the results offer room for both optimism and caution. Information campaigns may effectively shift perceptions, particularly if underlying facts are poorly understood and closely linked to policy preferences. However, planners must remain persistent—a single exposure to new information will be insufficient to change hearts and minds.