Increasing supplies of low-cost, readily available natural gas, along with expanding refueling infrastructure and increasingly strict vehicle emissions requirements, are driving strong growth in the market for light-duty natural gas vehicles (NGVs), Navigant Research says in a recent report. The total number of light-duty NGVs on roads worldwide will increase from 17.5 million in 2013 to 39.8 million in 2023, it says. In that year, NGVs are projected to account for 2.6% of all vehicles on roads. Growth is occurring in countries where a robust market for NGVs already exists—such as India, China, Thailand, and Brazil—and in countries where NGVs are a relatively small niche, such as the United States and Germany. Navigant says the market for light-duty NGVs is not homogenous around the world or even within regions. In North America, the market is heavily focused on fleet purchasers, while in parts of Western Europe, Latin America, and Asia Pacific, the consumer market plays a much bigger role. Whether a particular market is focused on fleets or private consumers has a significant impact on the NGVs available. In North America, the fleet market for NGVs remains relatively small, so automakers are content to rely on vehicle conversions by companies that complete the conversion prior to customer delivery.