Remote sensing is potentially the best option for fleet emissions monitoring, the development of an emissions factor, the identification of individual high- or low-emitting vehicles, and the screening for groups of high-emitting vehicles for market surveillance. The development and use of remote vehicle emissions sensing has been growing in recent years. Data has been collected from all continents except Antarctica, with more than 1 million measurements per year collected in China, the United States, Hong Kong, and Korea, and more than 1 million measurements since 2010 in India. In Europe, data collection activities have been mostly in western countries—with more than 1 million measurements since 2010 in Spain—and northern countries.