-consistent policy rules that implement the stochastic first best as long as a future market exists. We apply our theory to carbon …

infeasible. Most countries instead rely on exhaust standards that limit air pollution emissions per mile for new vehicles. We … assess the effectiveness and efficiency of these standards, which are the centerpiece of US Clean Air Act regulation of … spectacularly, by over 99 percent, since standards began in 1967. Several research designs with a half century of data suggest that …