Hey, my trunk is small. :-(
This is something that I would be interested in. I like the locking gas cap idea. Normal rally races judge by times through legs of the race. However, since we judging based on fuel economy, not speed, we should focus on something other than time. Prearranged gas stations could be set up in 300-500 mile increments (the legs), and each vehicle would be ranked by the fuel consumed during that leg. If you can't make the gas station without breaking into your "emergency envelope," it would be the equivalent of breaking down in an actual rally.
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