Well, my own understanding from within the English language is that they could easily be considered as falling under the generic present tense's state outside of time. The routes run over and over and over, and so one could use the simple present in the same way literature is described in the present because a book's events are outside time and new again for each reader.
Per Lieselotte Anderwald (Language between Description and Prescription, p. 52), on the other hand,
...the use of the simple present to refer to future time is occasionally mentioned in nineteenth-century grammars, although the specific circumstances that allow this use today (sometimes called the 'timetable' future...) are never mentioned. Nevertheless, something similar to the present-day constraint that Leech calls 'a plan or arrangement regarded as unalterable'... can be deduced from the nineteenth-century examples given. Thus, Wells gives as an example 'he leaves in half an hour'..., Mulligan proposes 'John WRITES to his father next Saturday. He GOES to town to-morrow. Here the action is future'..., and Rushton says that 'we must remember, that in modern English there is no distinct inflection to represent the future; and that, especially in common conversation, we employ a present tense with a future signification: as 'I go to London to-morrow,' 'He comes down next week"... All these examples are compatible with a reading of the present tense indicating a future 'plan or arrangement as unalterable'. Towards the end of the century, Whitney and Lockwood claim that we use the present to refer to the future 'when we wish to make it vivid and distinct... He enters college next year,' but surely this characterization better applies to the historic present (which they mention at the same time...)—their future example again fits the restricted context of the 'timetable' setting that is described for the futurate use of the present today.