To reduce traffic, DOTs need both “carrots” and “sticks”

Nearly every state DOT is grappling with how to reduce traffic and carbon emissions—many states developed official , and congestion relief is often at the top of a DOT’s priority list. But a new study from Swedish researchers says that some of the most common ways to address these challenges—using only “carrots” rather than “sticks,” in the researchers’ words—may leave states struggling to achieve their goals.