This is for the wagon version but i think it is a pertinent press release from BMW:
"Safety engineering and features: improving on a star performer
New Head Protection System (HPS). The first front-to-rear Head Protection System to be offered in the 3 Series employs a curtain-type system, which takes up less space in the headliner and can remain inflated for several seconds after deployment, especially important in case of rollover.
New seat-mounted front side-impact airbags. The 3 Series is BMW's first to employ seat-mounted side-impact airbags, as opposed to the door-mounted type of the predecessor and other current Series. In their function of protecting occupants' pelvis and thorax regions in side impacts, the seat-mounted airbags are equal to the door-mounted type, but offer greater freedom for the interior designers to achieve their functional and esthetic goals.
Automatic safety-belt tensioners and force limiters front and rear. Long standard on BMW front safety belts, these features now enhance the outboard rear belts' effectiveness as well.
New occupant-detection sensor. BMW has long employed a sophisticated electronic control strategy for managing the deployment of airbags and safety-belt tensioners. This approach to optimal effectiveness of safety systems now becomes even more precise, thanks to a new sensing mat in the front passenger seat. Called OC3, the mat is more highly sophisticated than its predecessor; it measures the weight and analyzes the pressure distribution of the occupant in order to distinguish between an adult and an infant in a child safety seat. The front passenger's airbags will be deactivated, should the driver install a forward-facing infant safety seat.
New features for protecting the driver's feet and knees. Two measures have been taken to reduce the likelihood of injuries to the driver's feet and legs:
- The footrest is designed to crush under the force of the driver's left foot in certain frontal impacts, so that the full impact force is not transmitted to his or her foot and leg.
- The Mastervac (brake master cylinder) is mounted so that as the front end deforms, it rotates, and with it the brake and clutch pedals. The pedals move forward, canceling much of the force transfer to the driver's feet and legs if they are on the pedals.
And for the first time, the 3 Series Sports Wagon offers LATCH attachments on the front passenger's seat as well as the two outboard rear seats for optimum safety with up to three children in the car. "