Global sales of autonomous vehicles will reach nearly 21 million vehicles by 2035, a substantial increase from previous estimates, according to a forecast from auto industry information firm IHS Automotive.

Roughly 600,000 autonomous vehicles on roads around the world by 2025, and that number that will grow substantially every year between 2025 and 2035, the forecast says.

The U.S. will lead the world in early adoption of autonomous vehicles, while Japan will simultaneously ramp up industry coordination and investment ahead of the Summer Olympics in Tokyo in 2020, IHS says.

IHS forecasts predicts that by 2035 nearly 4.5 million autonomous vehicles will be on U.S. roads.

The uptick in the expected sales numbers is driven by recent research and development by automotive original equipment manufacturing, supplier and technology companies that are investing in this area, according to IHS.

IHS says its new forecast is also based on recent developments and investments in this sector of the market, as well as activity within various regulatory environments.

While the forecast is for global sales of autonomous vehicles to reach nearly 600,000 units in 2025, Egil Juliussen, Ph.D. and director of research at IHS Automotive, said the new forecast also reflects a 43 percent compound annual growth rate between 2025 and 2035, which he terms “a decade of substantial growth as driverless and self-driving cars alike are more widely adopted in all key global automotive markets.”

IHS expects manufacturers to create entirely new vehicle segments in addition to adding autonomous capabilities to traditional vehicles. ”

The U.S. market is expected to see the earliest deployment of autonomous vehicles as it works through challenges posed by regulation, liability and consumer acceptance, according to HIS.

IHS Automotive forecasts that despite a later start, the largest market, China, will see sales of more than 5.7 million vehicles equipped with some level of autonomy by 2035.

Major markets in western Europe will maintain industry technology leadership through the premium segment, with a little more than 3 million autonomous vehicles expected to be sold in 2035 and another 1.2 million vehicles in Eastern Europe. IHS Automotive also forecasts more than 1 million vehicles with some level of autonomy in the Middle East and Africa in 2035, with the potential for new and innovative business models and use cases.

In Japan and South Korea collectively, IHS Automotive forecasts indicate nearly 1.2 million vehicles will be enabled with some form of autonomous driving capability by 2035. Demographics and an affinity for technology and innovative solutions help both markets, as the Japanese auto industry unites to close the gap with U.S. and European rivals and as South Korea continues its development of world-class capabilities.