The point is to use the movement of the buses as if they were movements of a cinema camera. This , such as travellings, zooms, or a great angular lens.

In terms of efficiency, considering that the action was a brand action (Sitges Film Festival sponsorship) not a product one, we can say it was very notorious since the bus lines selected ran all over Barcelona and all the way to Sitges. But quantitative efficiency records cannot be taken from this brand action.