Prices of tradable credits in environmental regulations reveal information about abatement costs. This information guides regulatory assessments and future changes to the regulations. When regulations overlap, however, simple interpretations of credit prices no longer hold. We derive formulas for interpreting the value of credit prices for three overlapping regulations for passenger vehicles: corporate average fuel economy (CAFE) standards, greenhouse gas (GHG) standards, and zero emissions vehicle (ZEV) programs. Our assessment reveals that the marginal costs of reducing GHGs from conventional gasoline vehicles are virtually equal to the sum of CAFE and GHG credit prices, since each policy regulates emissions/fuel use in nearly the same way. We calculate that marginal costs ranged between $8 and $16 per ton of carbon dioxide in 2017. In contrast, marginal costs of selling one additional ZEV were $6,000 to $11,000 in 2017, which are higher than the ZEV credit price. This difference is because selling an additional ZEV yields compliance cost savings under the CAFE and GHG programs.

环境法规中可交易信用的价格揭示了有关减排成本的信息。该信息指导监管评估和未来对法规的更改。然而，当监管重叠时，对信贷价格的简单解释不再成立。我们推导出解释乘用车三个重叠法规的信用价格价值的公式：企业平均燃油经济性 (CAFE) 标准、温室气体 (GHG) 标准和零排放汽车 (ZEV) 计划。我们的评估表明，减少传统汽油车温室气体排放的边际成本实际上等于 CAFE 和温室气体信用价格的总和，因为每项政策都以几乎相同的方式调节排放/燃料使用。我们计算出 2017 年每吨二氧化碳的边际成本在 8 美元到 16 美元之间。相比之下，2017 年，额外销售一辆 ZEV 的边际成本为 6,000 美元至 11,000 美元，高于 ZEV 信用价格。这种差异是因为在 CAFE 和 GHG 计划下，销售额外的 ZEV 可以节省合规成本。