Electric cars are essentially less efficient standard cars in most of the US considering we get most of our power in those areas from coal/oil, so you're still using fossil fuels and putting particulates into the air but you're also limited to a short range. Solar power is great and all but honestly in most of the United States it won't work, get serious with yourself. I'd love to see you try to run a solar car in Washington, it might work out ok for two or three months of the year before the endless clouds of fall, winter, and spring roll in.
What we really need is a ductile room temperature superconductive material to replace our shitty copper wire for transmitting electricity. You know why birds love to rest on power lines? Because the majority of power generated is wasted as heat while traveling through lines, a superconductive wire would make our current infrastructure ridiculously powerful, combine it with more research into solar, tidal, wind, and geothermal energy and we could do away with fossil fuels pretty easily in the US.
We could make a ridiculous amount of solar power in Nevada, which is about 90% uninhabited sunny wasteland anyways. Wind energy is readily available all through the midwest, tidal energy can be drawn from most places on the coasts, and we've got the Cascades and the Yellowstone area as two major geothermal hotspots that could potentially be exploited. All of that hinges on a much more effective transportation method though.
I suppose that's not very relevant to cars though, Hydrogen is the next likely technology, it has its kinks but it shows more promise than anything else. Biodiesel cuts into the food supply and still gives off emissions, both of which are bad for us.