The self-driving car market is beginning to rev up. Japanese car maker Toyota on Tuesday announced that it planned to have self-driving cars commercially available by 2020 — the same year Nissan, General Motors and Google plan to have autonomous vehicles on the road. Toyota revealed that it has been testing its self-driving technology with a car called the Highway Teammate, a modified Lexus GS that’s been cruising around Tokyo’s busy Shuto Expressway. It has…