Plenty of experimental vehicles have achieved this level of streamlining before, but what makes the SIM LEI different is that it's a car you could actually see a small family using as its primary vehicle. Or at least in Japan, where small cars are already the norm. The car is unusually long for its width, in order to accommodate cargo and further reduce its air resistance.
Despite its makers' devotion to practicality, measures undertaken to make the car displace as little air as possible are pretty extreme, from stubby rear-view mirrors to side-impact beams placed on the outside of the vehicle's doors to make the vehicle 4 inches narrower.
The car's rear view is so bad, in fact, that its rear view mirrors are supplemented with a trio of screens hooked to rear-facing cameras, including one that feeds a 19 inch display, giving the driver an extra wide-angle view of what's behind. It's a good thing, too -- if more than a few of these make it onto the road, you can expect to see drivers trying to extend their range by drafting each other on the highway, like cyclists on the Tour de France.