The street scene was taken up first, and probably repeated several times. Maybe with only one car?
The arms were with chroma matte, or blue / green screen free and conducted to the rhythm of the music in roughly the right position. The Lighting of the arms has been adapted to the sun.
The arms have but in contrast to the (real, after football ballet-style cut) cars do not correct shadows on the street is synonymous with the gloss on the car roofs do not see any reflection. While this does not detract from the effect, however, reveals that it has been made as described above.