What good will that do when there are so many disabled vehicles in your path?
Even if all the cars were moved off the road, how long will the remaining diesel last?
Would it be more useful to re-start civilization or worry about how much gas you can carry with you?
Personally, I would want to work within my neighborhood and community to get life back to "normal" as swiftly as possible. I'm thinking that would mean limiting distribution of diesel to trucks, trains, and ships to carry goods to the stores.
Well, where I live there is not so many cars that they completely clog the roads. See also my above post about the ATV. Which is gas, smaller than a car, and goes off road. The gas would go bad long before you used it up, and you could also use it to power a generator for at least lights, if you had the generator parts, too.
I don't think distributing diesel to the trucks, trains and ships would do any good, the EMP wiped out all those, remember?