Don’t recall ever touching upon this, but it was discovered that they had roofracks available in the GC version (At least the models do). I’ll need to find out if they had any function, but regardless, they will be added to the game. Could possibly be used for additional fuel later on should that get properly implemented.
Also the fine folks at Dreamcast Talk will be playing vanilla 4x4Evo1 on Wednesday @ 10PM EST. More info here, come join in! More info here -> http://dreamcast-talk.com/forum/viewtopic.php?f=4&t=4521