Just five milliseconds is all the BMW 5 Series Touring takes to detect an impact, calculate its severity and to inflate up to eight airbags. A high-speed optical bus system controls the precise timing and extent of inflation of each airbag. The improved head airbag system (Advanced Head Protection System) protects occupants in a side impact by inflating side airbags and a protective curtain airbag across the side windows. At the same time, the occupant restraint system and Active Headrests (if the optional Comfort Seats are fitted) are activated as required.