Yahya related to me from Malik that he had heard that AIi ibnHusain used to say, "The Messenger of Allah, may Allah bless him andgrant him peace, would join dhuhr and asr if he wished to travel thesame day, and he would join maghrib and isha if he wished to travelthe same night."
USC-MSA web (English) reference: Book 9, Hadith 7
Arabic reference: Book 9, Hadith 335