People have definitely been tossing this idea around - basically your micro-car could "tow" a 10-ton self-powered autonomous trailer that locks in on guide sign

People have definitely been tossing this idea around - basically your micro-car could "tow" a 10-ton self-powered autonomous trailer that locks in on guide signals from the rear and drafts your car. Much, much simpler than true autonomous driving - you don't have to read road signs, watch out for cyclists crossing against the light, figure out how to handle a 6-way uncontrolled intersection, etc. You'd probably want some feedback to the lead vehicle to modulate acceleration and braking to match the capabilities of the trailer.