worldwide radar-assisted Autonomous cruise control system, and a cylinder deactivation system called Active Cylinder Control for the S 500 and S 600 models, which improves fuel consumption and reduces emissions. All were pioneering innovations at the time of the W220's conception. There are standard features to all models, standard features to certain models, and finally optional features. Sometimes what is standard changes on a model year or country of sale. 4Matic all wheel drive was introduced to the North American S-Class for 2003, for the S 430 and S 500 as a US$2180 option. This full-time system splits engine power 40/60 front/rear, with electronic traction control adjusting that mix to the wheels (or wheel) with the best traction in slippery conditions. It was the first Mercedes with curtain airbags (previewed by the F200 concept in 1996). Details on some of the safety, comfort, and technological features are as follows: Safety Despite a wide range of safety technology, and being marketed for its safety, one Canadian website said W220 S-Class had not actually been tested by the Insurance Institute for Highway Safety, the National Highway Traffic Safety Administration, or Euro NCAP, or at least the information was not available. However, another website says that the W220 passed the legally prescribed EU front and side impact tests. Increased attention to side impacts was noted, and the car included a window air bag that inflates between the A and C pillars. Passive safety features include various frames and bulkheads made out of aluminum and/or high-strength steel. Also the front and rear ends include aluminum crash boxes can be replaced as separate units to reduce the cost of repairs. Despite its price German insurance companies put it in the lower bracket because it was easier to repair. Pre-Safe, the integrated Mercedes-Benz collision avoidance and response system, debuted with the W220 S-Class facelift in late 2002. Electronic Stability Program (ESP) and Brake Assist were standard features for difficult driving conditions and emergency maneuvers. The W220 S-Class added standard front and rear side curtain airbags. In total, the W220 features 8 airbags: 2 frontal (driver and passenger), 4 side airbags (one in each door) and 2 window-airbags. LED brake lights were also standard issue on the W220. LED brake lights illuminate faster than conventional bulbs. Comfort and convenience Features varied depending on locality (e.g. North American version) and what options were equipped Distronic cruise control, which