A more realistic goal would be the incremental replacement of internal combustion cars with electric cars. Something like 30% in 10 years would be a tremendous good and would seem possible. I think the ultimate goal should be 85% electric vehicle use. I suspect that there will be a last 15% of uses for which the IC engine will still be the most cost effective solution.
Actually you can right now get electric cars from Zap or GEM for less than $20K which are suitable for commuting provided your commute is very short and very slow. I'd be tempted to get one myself if I actually had a garage. But we're nowhere near anything that could be called a replacement for a real car, rather than a supplement to one.
http://www.popularmechanics.com/automotive/new_cars/4237853....
It's no good saying that the price would magically come down immediately if they were produced in sufficient quantities. If anyone had the ability to build a $20,000 long-range four-seat electric car they'd sell millions of 'em anyway.
The technology for cheap and practical electric cars will arrive eventually, but it's probably still a decade away. When you can buy a decent electric car for $20K then people are going to convert anyway, with no need for a huge scary government program forcing them to do so.