The control of mobile-source pollution began with a focus on conventional pollutants that imposed a risk to human health. This chapter deals the regulations designed to protect human health and how those regulations evolved as concerns over climate change heightened. Fuel economy standards are designed to reduce reliance on fossil fuels and to reduce emissions from vehicles. The Gas Guzzler Tax is levied on cars that do not meet fuel economy standards. The European Union has tackled the externalities from fuel consumption primarily through gas taxes and has some of the highest gas taxes in the world. The pricing of transportation falls into several categories: fuel taxes; congestion pricing; emissions pricing; pricing of accident externalities; pricing of roads; and pricing or subsidizing public transport. Vehicle purchases, driving behavior, fuel choice and even residential and employment choices must eventually be affected by the need to reduce mobile-source emissions.