Upvote:2
If the question is βalong a straight lineβ, ignoring roads (so more likely in an aircraft rather than in a car), the answer is at least 12:
The line is actually less than 1200 km, and goes through:
I'm not sure there are many places outside the Balkans where you can find that many countries in such a short distance.
If the question is "along actual roads", then I haven't managed more than 8 for now: