In the opinion of accident researchers, in side-impact collisions top priority should be given to protecting the head. However, the side airbags so far offered and installed in production cars are systems primarily dedicated to protecting the upper part of the occupant's body. Introducing a side airbag system for the head area proved to be very much more difficult. For this reason systems such as the ITS presented by BMW are appearing on the market with something of a delay compared with the thorax airbag. In order to assess the various approaches adopted for this specific form of protection system, we must define the requirements, describe the test procedures and draw up a form of "shopping list" to permit comparisons to be made.