The traveler is not considered a traveler unless he leaves the built-up area with his body

The traveler is not considered a traveler unless he leaves the built-up area with his body
When a person leaves his town, when does he pray the shortened prayer: with the intention of leaving, or after leaving the built-up area?
The traveler is not considered a traveler until he leaves the built-up area, but this does not mean leaving by sight; rather, it means leaving with his body, even if there is only an arm's length between him and the town, for he may then avail himself of the dispensations of travel.