WHAT IS IT Conceived out of the World Solar Challenge. This year’s event is split in two: a world rally for solar-powered cars with entries from 17 countries; and production or near-production cars to test fuel efficiency and emissions using a variety of power sources. ENTRIES 21 production and 38 solar cars. WHEN October 24-30. THE ROUTE Darwin to Adelaide, with overnight stops at Katherine, Tennant Creek, Alice Springs, Coober Pedy and Port Augusta before finishing in Adelaide. HOW IT’S JUDGED The car that delivers the best improvement on its official fuel consumption rating over timed stages will win. Entries must hold a minimum average speed and stay within posted speed limits. WHY IT’S IMPORTANT It showcases fuel-efficient cars of all sizes, most of which you can buy now.