The Citroën C4 is a small family car produced by French automaker Citroën since autumn 2004. The C4 was designed to be the successor to the Citroën Xsara. It is mechanically similar to the Peugeot 308, which was launched in 2007. A revised version with new front end and dashboard revisions was launched for the 2008/09 model year. A major selling-point of the Citroen C4 is its extensive use of technology. For example, the car features the Lane Departure Warning System, which alerts the driver if he or she crosses a road marking without using the turn signals; directional headlights; perfume dispenser integrated into the ventilation system; translucent dashboard, transparent glass roof; ESP, and a fixed steering wheel hub which lets the driver operate several functions of the car without removing his or her hands from the wheel. The fixed hub also allows for the first production use of a shaped driver airbag. Because the hub maintains a constant position, the airbag can be optimally shaped to spread the load across the greatest possible area of the driver's body in a collision, thus reducing the chances of serious injury. In addition, the car features an innovative centrally mounted translucent LCD speedometer display that remains clearly visible in all lighting conditions. Surprisingly, given the emphasis put on technology, the Citroen C4 In-Car Entertainment, while well integrated into the car's information system via CAN Bus, is not DAB ready. MP3 playback is supported by the entry level audio system and high-end audio with double layer sound insulated windows and integrated navigation system is available as extra. . The Citroen C4 does not feature Citroën's hydraulic suspension, which is reserved for higher class models, such as the C5 and C6. The Picasso version can get a pneumatic rear suspension. Underneath, the Citroen C4 uses an identical mechanical design to the contemporary Peugeot 307. Interestingly, its underpinnings date back to the 1991 Citroen ZX, although it is a huge leap forward over that and the Xsara that was produced between the ZX's demise and the C4's launch.