Border patrol on Shabbos

Hi,

One who will need to ride in a vehicle on Shabbos for the purpose of a safety patrol may take food as needed for the trip, even if he will ride beyond the biblical techum. (On Shabbat, one may not travel more than a kilometer outside of a settled area; this boundary is called techum, and there is some debate as to whether it is biblical or rabbinic. All agree that there is a biblical prohibition against travelling beyond six kilometers.) However, where the trip is short enough to permit it, one should simply eat beforehand.

One may not bring books for reading, including for prayer or learning Torah. Even where the books are not heavy enough to increase the use of gasoline, one may not transport them beyond the aforementioned techum.

(Rav Moshe Feinstein, Igrot Moshe Orach Chaim 5:26)

Have a great day,
Mordechai