1.When a person is travelling with the intention of proceeding fortyeight miles or over from his home he should shorten the obligatory prayers of four units to two each. The curtailment is applicable to the (Zuhr) Prayer, the Mid-Afternoon (Asr) Prayer, and the Evening (Isha) Prayer. The Early Morning (Fajr) Prayer and the Sunset (Maghrib)Prayers remain unchanged .
2.This advantage remains effective even after the traveler arrives at his destination, if he does not intend to prolong his stay there for fifteen days or more. Otherwise, he should offer the reducible prayers in their original and complete number of units.
3.While traveling under these circumstances, he is exempt from all supererogatory prayers (Sunnah) except the two Sunnah units of the Early Morning (Fajr) and Witr which follows the Evening (Isha) prayers.
There are some minor differences of interpretation between the various schools of law regarding the travel distance and the travel duration.