Since the hardships of travel are no longer the way they used to be in the Prophet’s time, are we still allowed to shorten our prayers? If yes, then after what distance? By how many rak‘ats? Why has this directive not been adapted to the passage of time?
Answer: As a principle, it is true that all directives which are conditional, do not apply in circumstances in which the conditions no longer exist. The directives which pertain to shortening of prayers in travel are conditional to the feeling of unease and discomfort a traveller experiences in his journeys. This, of course, may be relative and different for different sorts of people as well as for different forms of travel. In spite of better travelling facilities, a traveller may still feel the discomfort and uneasiness which is associated with travel. Besides, comfortable travelling is still not affordable to many. Similarly, a traveller may feel very fresh in a relatively hard and long travel.
Consequently, if, after travelling -- whether through tough means or comfortable ones -- a person feels as if he is at home, it is not obligatory for him to shorten his prayers. Because of variety and difference in human temperament, the distance after which this rebate can be benefited from has not been fixed. It is left to the traveller to judge for himself.
As far as the shortened rak‘ats are concerned, they are clearly specified by the Sunnah. The farāid of Fajr and Maghrib prayers, being already small in number are not shortened, while in the three remaining prayers they are reduced to two.