TOKYO --- Toyota said last week the company has developed a plug-in hybrid vehicle that is ready for public-road tests in Japan. Toyota also has plans to test the vehicles on public roads in the U.S. and Europe. Prototypes will be made available to the University of California at Irvine, University of California at Berkeley, and the U.K.'s Ministry of Land, Infrastructure and Transport. In California, Southern California Edison, the Energy Commission and the South Coast Air Quality Management District will be among the parties participating in the study, according to a report in Orange County's Daily Pilot newspaper. According to a report from Edmunds.com, the test fleet in Japan will include eight plug-in hybrid vehicles used by the government. The vehicle batteries will be recharged using household electric power. "Although challenges still exist in the development of pure electric vehicles, such as a limited cruising range and issues related to cost, TMC still views plug-in hybrid vehicles as a promising technology for allowing electricity to serve as a viable power source for automobiles," Toyota said in a released statement. The prototypes will be "powered by oversize packs of nickel-metal-hydride batteries that effectively simulate the level of performance Toyota expects to achieve when it eventually develops its own more advanced, compact and powerful battery systems," Toyota said.