travel - How do I do the car-door-sukkah trick?

I know in theory, people on the road don't need to eat in a sukkah; at the same time, you're not supposed to go put yourself in that situation on purpose. ("Let's go take a chol hamoed trip -- oops we're travelling, no need for sukkah.")

I heard in yeshiva that if you keep schach in your car (let's assume a mat), you could open the front and rear doors on one side (leaving the other doors closed), put schach up between the open doors, and sit (low to the ground, I assume) in that small space. (See awful ASCII art, if that helps.) The doors are two walls (assuming they're lavud to the ground and tall enough), the third wall is the other side of the car (dofen akuma.)

Has anyone ever heard of this or tried it? Which dimensions on a car are needed? (Where can I see those dimensions listed?) Any other thoughts?

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