No, the number is the number of miles you have driven. So "within the next two miles" means you need to check (number + 1) and (number + 2). Return 1 if either of those are "interesting" (and the original number was not interesting).

E.g. 122 is "almost interesting" because 123 is interesting. 121 is interesting in its own right because it's a palindrome.

Also, your question shouldn't be marked as a spoiler.