Travel Behavior and Older Vehicles: Implications for Air Quality and Voluntary Accelerated Vehicle Retirement Programs

Older vehicles contribute a significant and disproportionate share of the pollution in urban areas. Starting in 1990, several areas adopted voluntary accelerated vehicle retirement (VAVR) programs to address this problem and to respond to demands for flexible, market-based approaches to controlling air pollution. VAVR programs offer owners of older vehicles cash to scrap their vehicles. VAVR programs have been adopted throughout the U.S. and abroad, though not without controversy and uncertainty over the programs’ benefits. This research first examined the roles of older vehicles in U.S. households. Lower income households are more likely to own older vehicles and to rely upon them more for their daily transportation needs. While older vehicles are generally driven less than newer vehicles, they serve a wide range of roles within households. This makes estimating the emissions reduction benefits of VAVR programs more difficult. This research then examined how household characteristics and behavior influence participation in VAVR programs and, therefore, the benefits from the programs. The assumptions used by regulators to estimate the air pollutant reductions from VAVR programs are compared with data from VAVR programs in California. Changing the assumptions did significantly change the estimated benefits. However, in nearly all the scenarios examined, the programs still reduce emissions significantly, particularly of reactive organic gases. Data from surveys of program participants show that the programs are diverting vehicles from the used vehicle market, which is not built into the current assumptions for estimating program benefits. The scrapped vehicles are generally in poorer condition, are worth less, and are driven less than other older vehicles. However, the criticism that most of the scrapped vehicles were headed to the junkyard anyway appears unfounded. Nearly all of the scrapped vehicles were replaced with another vehicle and nearly all of the replacement vehicles were newer than the scrapped vehicles. Policymakers should consider ways to expand, improve, and/or supplement VAVR programs. First, adjustments to the methodology to calculate emissions reductions should be made to make the estimates more conservative. Second, policymakers should explore ways to change and supplement the programs to address key factors that reduce program effectiveness. Current programs are missing certain households that drive older vehicles a lot and have little impact on the vehicle replacement decision. Promising options include repair programs, targeting certain vehicles for participation in VAVR programs, and increasing the incentive for households that replace the vehicle with significantly cleaner alternatives.