Allowing single-occupant low-emission cars in California to use high-occupancy vehicle (HOV) lanes on congested highways exacerbates the congestion and causes up to about $4,500 per car in adverse social costs annually, including increased commute times and carbon dioxide emissions, according to a new study in the American Economic Journal: Economic Policy. The authors, from Cornell University, University of Colorado, UC Irvine and UC Berkeley, calculated that the Clean Air Vehicle Stickers (CAVS) policy results in a best-case cost of $124 per ton of reductions in greenhouse gases; $606,000 per ton of nitrogen oxides reduction; and $505,000 per ton of hydrocarbon reduction—exceeding those of other options readily available to policymakers. The California law enabling single-occupant access to the HOV lanes was meant to stimulate sales for fuel-efficient, ultra low-emission […]