Aside from the state’s longtime role as a trend incubator, other factors have combined to make this a test bed for what proponents hope will be a new age in personal transportation. The state’s policy makers have set tough emissions rules mandating a rising number of zero-emission vehicles, and they’ve offered tax incentives for buyers. As a hotbed of high technology and entertainment, California has plenty of influential early adopters with ready cash. An expanded charging infrastructure is being developed and, perhaps most important, battery-powered cars grant access to the coveted car-pool lanes on congested freeways. Among the most anticipated electric models of the summer is the Tesla Model S luxury sedan, with base prices of $58,570 to $78,570, depending on the size of the battery pack and, consequently, the driving range on a charge. While the car was under development, Tesla collected more than 10,000 reservations without so much as a test drive. Once promised for delivery in 2009, the S — Tesla’s second model — at last reached customers on June 22.