Do the math right.
The article stated 1 Bushel produced 5 gallons of fuel.
THe demonstration site listed an average of 50 bushels per acre.
That is 250 gallons per acre. Per year (more is you get 2 crops from the same land).
Burning 5 gallons per week (150 miles per week @ 30 mpg)would allow 1 acre to supply fuel for 1 vehicle for 50 weeks.
who only burns five gallons per week? I didn't do that when I lived a mile from work! I burn a tankful of gas (14 gallons) per week, maybe a tad more, and most people have longer commutes than I.
but even if we use your figures, one acre per car per year, there are how many cars in the US? 150 million? how soon before you can have a significant portion of that acerage in production?
How much diesel fuel does the tractor cultivating the soybeans burn cultivating that acre. Subtract that out to get your net left for your car..