The photo features in both 'Joel Meyerowitz - Where I Find Myself' (a life-time retrospective written by Meyerowitz) and 'Joel Meyerowitz' by Colin Westerbeck. In the latter book it says "This photograph was made from a moving car, part of a series that came about while travelling in Europe for a year." It is titled "1966 London". I see no reason to question the veracity of either the image or the man himself.