As a general response to uncertainty, half-speed can have advantages. Specifically:
Now, neither of these were applicable in your specific hotel case - had there been anyone to ask, you could have stopped and asked, and going slowly in a car doesn't really help you. So it makes a lot of sense to ignore the default strategy in that case - and, in fact, in several other cases as well (it's a common heuristic, but it really doesn't apply in a lot of situations)
Related to: Half-assing it with everything you've got; Wasted motion; Say it Loud.
Once upon a time (true story), I was on my way to a hotel in a new city. I knew the hotel was many miles down this long, branchless road. So I drove for a long while.
After a while, I began to worry I had passed the hotel.
So, instead of proceeding at 60 miles per hour the way I had been, I continued in the same direction for several more minutes at 30 miles per hour, wondering if I should keep going or turn around.