this is psychological, nothing more. one does get bored on long drives and there is nothing like a snack stop to relieve the boredom. don't fall into that trap.
i often do not eat when on long drives. not fasting per se, but the point is- you aren't doing anything. you are not expending a lot of energy, you don't need to put any energy in. fasting creates an alert state, i find, but if you think you are getting sleepy, pull over and nap.
i don't know specifically what you are worried will happen if you fast and drive,
so i hope this helps.