I am in the same position, feeling imbalance while driving in the highway, it all started after the viral eye conjunctivitis an year ago. The condition was much improved but still not very confident when driving in the highway. God should help us.
correction: buclizine not buclizide
Hi.
These symptoms can be explained by similar mechanisms as that of sea-sickness, where the inner ear fluids are sensitive to minor changes in position. You can also notice this phenomenon among other people who has a tendency to vomit or become dizzy while traveling long distances in a land or sea vehicle. There are medications to control these symptoms such as meclizine and buclizide that can be taken before you hit the road, but you should discuss this first with your doctor.
Another possibility is postural hypotension, which means that your blood pressure declines when sitting for a long time. The driving position can cause blood and fluid to pool in your lower extremities therefore somewhat starving your brain with oxygen (much like what happens to fighter jet pilots in high G situations).
I suggest that you have yourself evaluated by your doctor for these possibilities.
Regards.