could maintain a set distance between the S-Class and any vehicle in front. Speedtronic adjustable speed limiter for not exceeding a set speed on roads with speed limits. Optional Keyless Go, a smart key entry and startup system. Rain-sensing windshield wipers. Light sensors to turn the headlights on and off automatically, depending on lighting circumstances. The instrument display and the COMAND screen's backlight and colour also adjust automatically depending on the ambient light situation. Parktronic visual and audible parking aid, with sensors in the front and rear bumpers. Also, the passenger side mirror can swivel down automatically when engaging reverse, to help see the curb. Automatically heated exterior mirrors. Fully automatic climate control system with pollen and charcoal filters and optional separate rear-seat climate controls. The system features a sensor that is able to detect the sun's position. This allows for individually variable system adjustments based where the sun's rays are most intense. COMAND system combines the controls for audio systems, the television, the navigation and the telephone. COMAND based cars offer higher quality audio compared to the Audio 10 system. Optional BOSE sound system. Summer Open/Close - Ability to open and close all four windows and the sunroof at the same time upon entry and/or exit from the vehicle. Self opening and closing trunk. Self-closing doors via pneumatic system. Electrically adjustable seats are standard. Optional were the memory function for the seats (standard in many countries on the larger engine models) and the multi-contour backrests with massage function. Easy entry/exit function. Auto-dimming interior and driver's side exterior rear view mirrors to prevent being dazzled by cars behind. Xenon headlamps (bi-xenons starting from late 2002 facelift. These provide HID xenon lighting for both low and high beams). Linguatronic voice recognition system which can be used to control the audio system, navigation system, and a cellular telephone through voice commands. The Linguatronic voice control was introduced as an option in 1996 on the W140 S-Class. At that time it was primarily for controlling the car phone, and could understand 30 words. The second generation of this system was introduced in 2000. On the W220 this second generation system could understand more words and control more systems, such as the radio. In 2000, it could understand 300 words and control certain features on the phone, radio, CD player, and other systems. The second generation system needed 20 times the memory of the