Coaster is widely used in Japan, Singapore, Hong Kong, and Australia, but also in the developing world for minibus operators in Africa, the Middle East, South Asia, the Caribbean, and South America to operate as public transportation. Technology Hybrid electric vehicles Toyota is the world's leader in sales of hybrid electric vehicles, one of the largest companies to encourage the mass-market adoption of hybrid vehicles across the globe, and the first to commercially mass-produce and sell such vehicles, with the introduction of the Toyota Prius in 1997. The company's series hybrid technology is called Hybrid Synergy Drive, and it was later applied to many vehicles in Toyota's product lineup, starting first with the Camry and the technology was also brought to the luxury Lexus division. , Toyota Motor Corporation sells 44 Toyota and Lexus hybrid passenger car models in over 90 countries and regions around the world, and the carmaker has sold over 15 million hybrid vehicles since 1997. The Prius family is the world's top-selling hybrid gasoline-electric vehicle nameplate with almost 4 million units sold worldwide as of January 2017. Besides the Prius, Toyota's current hybrid lineup includes the Alphard/Vellfire/Crown Vellfire, Avalon, Aqua, Camry, C-HR/IZOA, Corolla/Levin, Corolla Cross/Frontlander, Crown, Harrier/Venza, Highlander/Kluger/Crown Kluger, Innova, Noah/Voxy, Raize, RAV4/Wildlander, Sequoia, Sienna, Sienta, Tundra, Urban Cruiser Hyryder, Yaris and Yaris Cross. The Lexus current hybrid lineup consists of the ES, IS, LC, LM, LS, NX, RC, RX, and UX. Plug-in hybrids The Prius Plug-In Hybrid Concept was exhibited in late 2009, and shortly after, a global demonstration program involving 600 pre-production test cars began. The vehicles were leased to fleet and government customers, and were equipped with data tracking devices to allow Toyota to monitor the car's performance. The vehicle was based on the third-generation Toyota Prius and outfitted with two additional lithium-ion batteries beyond the normal hybrid battery pack. The additional batteries were used to operate the car with minimal use of the internal combustion engine until they are depleted, at which point they are disengaged from the system. They are not used in tandem with the main hybrid battery pack. After the conclusion of the demonstration program, the production version of the Prius Plug-in Hybrid was unveiled in September 2011. The production Prius Plug-in had a maximum electric-only speed of , and the United States Environmental Protection Agency (EPA) rated the vehicle as having an range of in blended mode (mostly