Because it's substantially new for 2014, neither the Insurance Institute for Highway Safety (IIHS) nor the National Highway Traffic Safety Administration (NHTSA) carries over any crash-test scores for the Mercedes-Benz S-Class. Not that they've had any recently--it's so expensive, and sells in low volume, which puts it low on those agencies' priority lists.
Still, with Mercedes' long-standing reputation for occupant protection and advanced safety features, the S-Class should be a standout for safety, especially in light of its newest technology.
From that point, it may be easier to list safety gear the S-Class doesn't have. It doesn't come with a crossing guard. The stock models aren't up-armored.
It does, however, get available blind-spot monitors; lane keeping assist; adaptive cruise control with following and steering capability in traffic; forward-collision alerts and prevention with braking; and wipers with embedded fluid jets on both sides of the blades. There's also an available surround-view camera, improved night vision that can throw a spotlight on a pedestrian ahead, to warn them of oncoming traffic; and Active Parking Assist, which can guide the S-Class into either a parallel or perpendicular parking spot.
The list of safety features is exhaustive, no doubt. The S-Class' air suspension is programmed to compensate for heavy crosswinds by adjusting suspension stiffness; it factors in torque-vector braking, which applies braking to the inside rear wheel to tighten cornering. Attention Assist, an alert system that senses drowsy drivers and blinks a coffee-cup icon to suggest a rest stop, is standard on the S550, and now it works from speeds of about 35 mph to 120 mph. Finally, the adaptive cruise control has sensors in the steering wheel; keep your hands off the wheel for more than a few seconds, and the screen shows a warning--a pair of red-gloved hands.