The word route has two common pronunciations, namely [ruːt] and [raʊt]; you can listen to both forms here. However, it is not so clear which version is used by whom and in which context. In particular, it is not a simple matter of British vs. American English. According to Longman’s Pronunciation Dictionary, [ruːt] is used for almost all purposes in British English, except in the military context where [raʊt] is used. In American English, [raʊt] is used much more frequently (for example, my American climbing partners always used [raʊt]), but not exclusively. A good example is the infamous Route 66, which is usually pronounced as [ru:t] in songs and movies. A survey conducted for Longman’s Pronunciation Dictionary reveals that 2/3 of Americans say [ru:t] whereas 1/3 say [raʊt].