Oh, further info on that efficiency number: they ran with two strings of 12 batteries; and not the full compliment of 60 batteries. One set of 12 were the 33 pounders, and the second set of 12 were heavier, but the same power. And they are all used batteries...
The conversion factor listed on
Wikipedia is 33.4kWh/gal, so about 214MPGe? Just imagine what it could be with 400 pounds of lithium batteries and regenerative braking? Of course, that would require front wheel drive -- and so you could use more efficient electric motor, too!