| Abstract: | In recent years, communities have begun to implement both “soft” and mandatory policies designed to address worsening air quality. Voluntary or soft transportation policies have included air quality alert systems that encourage people not to drive on days when the air quality index is above a specified threshold and public education/action campaigns that focus on reducing automobile related travel. In this article, we evaluate the effectiveness of one such soft policy, the Clear the Air Challenge (CAC), in reducing ground‐level ozone during the Wasatch Front's summer ozone season. Using daily ozone data and color‐coded daily air quality designations from 2006 through 2012, we estimate a range of nonequivalent control group models. In only one of the models does the CAC generate a statistically significant but small reduction in ground‐level ozone. Future research should assess the full range of costs and benefits to the public associated with such soft transport policies. |
