Efforts to mitigate air pollution and noise are a complex endeavour as they involve addressing their sources, which vary depending on the country and region of the world and complex economic and geopolitical considerations. Measures such as mandatory or voluntary greenhouse emissions or fuel efficiency standards, shifting to lower-carbon fuels, legislating the use of motorized vehicles/kilometres driven, introduction of electric mass transit, congestion pricing/taxes, vehicle and fuel taxes, and advanced vehicle technologies (e.g. battery electric cars, hybrids, plug-in hybrids, and fuel cell cars) may help simultaneously alleviate air and noise pollution and climate change goals.