The S-Class has debuted many of the company's latest innovations, including drivetrain technologies, interior features, and safety systems (such as the first seatbelt pretensioners).

The major revision to the nomenclature scheme in 1991 renamed the S-Class with the "S" prefix that has three numbers for engine displacement in "centilitre" with no suffix for fuel type or wheelbase length.

Long-wheelbase models gained an L (for "Lang", German for "long"), reflecting an extra 10 centimetres (3.9 in) added in the rear passenger compartment.

This was a groundbreaking sedan for Mercedes-Benz, and for the first time in the company history, the car had an obvious, blatant and outward emphasis on safety placed above a pure styling viewpoint.

These safety features were all newly introduced passenger-car "firsts" on a production vehicle: padded door trim around the windows, heavily padded steering wheel (later to be replaced by an airbag with the Mercedes-Benz abbreviation of SRS standing for the English-language term Supplemental Restraint System), more comprehensive safety padding on the dashboard and around the interior, dual asymmetric windshield wipers, headrests with a center depression to locate the occupant's head in a more central position during a rear impact, a rain-water management system to improve visibility consisting of deep channels on both sides of the windshield and flowing into deeply channeled rain gutters, including similar designs on the side mirrors, rounded body shapes along the edges, such as the tops of the front fenders, etc., designed to ameliorate pedestrian injuries, ribbed rear taillamp lenses which would remain clearer of dirt on the recessed areas, an easy-to-access first aid kit stowed in a recessed compartment on the rear parcel shelf prominently labeled with the universally recognized "cross" symbol which represents "first aid", and several other subtle safety features related to both active and passive safety.

The W116 was larger on the outside than the W108/W109 series it replaced, but had similar interior capacity, as the additional bulk was driven by several new and aforementioned engineering developments on car safety and occupant protection in a crash.

Starting in 1975, the W116 was upgraded with a new fuel injection system to comply with revised exhaust emission standards in European markets.

A slight power reduction was a result of this update, but in 1978, a series of further engine upgrades restored original performance levels under the new fuel injection systems.

Due to the oil crisis, fuel efficiency was the major concern for the engineers, yet they still added also the high-performance, limited-production 450 SEL 6.9.

Every 450 SEL 6.9 featured a self-leveling hydropneumatic suspension, and offered the ABS anti-lock braking system as an option from 1978 onwards.

Also, in the United States and Canada only, Mercedes-Benz introduced the economical but powerful 3.0-litre 5-cylinder turbo-diesel OM 617 A producing 85 kW (116 PS; 114 bhp) in 1978, sold as the 300SD.

The interior featured additional courtesy and reading lamps, along with heated seats and a more advanced climate control system.

Although the top of range Mercedes-Benz 450SEL 6.9 of the previous generation was not directly replaced, the W126 carried forward the hydropneumatic suspension of the 6.9 as an option on the 500SEL.

[citation needed] The W140 cost 25% more than the W126 that it replaced and featured double-pane window glazing, self-closing boot lid and doors, electric windows with a jam-protection feature (lowering when encountering an obstruction), rear-parking markers in the US (which appeared on the rear wings when in reverse), and a heating system which emitted warm air while residual energy was available after the engine was turned off.

In 1995, the W140 received a minor face lift featuring clear turn signal indicator lenses on the front and rear as well as headlamps fitted with separate low- and high-beam reflectors for the US market.

The grille angle was adjusted to a slightly more upright position, and the xenon-discharge headlamps were given a new transparent housing, replacing the earlier opaque versions.

The interior is completely new, all materials have been upgraded and make for a more luxurious ride, and the center console transmission gear lever has been replaced with a column-mounted shifter.

This incident was later attributed to the radar system malfunctioning inside the radar-reflective (i.e. radar-confusing) steel test building where the event was filmed.

The Saks-edition S600 sedans were finished in a mocha black exterior with an almond beige interior and were the first examples of the S600 to be sold to private owners.

In 2007, Automobile Magazine named the W221 S-Class as one of its 2007 "All-Stars" over rivals from Lexus and BMW,[22] and Car and Driver selected the S550 as the winner in a five-way comparison test of flagship luxury sedans,[23] as did Motor Trend Magazine in July 2009 in a three-way comparison test, with the other two competitors being the BMW 750Li, and Audi A8L 4.2 Quattro.

Some interesting features include a large front grille inspired by the F700 Concept car and LED lights used exclusively inside and out — a first in the automotive industry.

Two strong converging character lines give the flanks a more sculpted look, while integrated exhaust tips and a large glass roof (likely optional) highlight the design.

Unlike previous generations, Mercedes focused primarily on the development of the longer model as many customers in the fast-growing Asian markets prefer to be chauffeured.

[26] Initially available only on 8-cylinder models and above, Magic Ride Control attempts to isolate the car's body by predicting rather than reacting to broken pavement and speed humps.

In the 1980s, Mercedes-Benz built the world's first driverless cars using the S-Class, together with the team of Professor Ernst Dickmanns at Bundeswehr Universität München.

[36] The culmination of this effort was achieved in 1995, when Dickmanns' re-engineered autonomous S-Class robot completed a trip from Munich, Bavaria to Copenhagen, Denmark and back.

[39] Passive safety features include: crumple zones in 1957 (vehicle body structure absorbs the force of impact); collapsible steering column (prevents the steering column from protruding into the cabin during accidents), strengthened occupant cell enhanced occupant protection during severe impacts (rollovers); pre-accident seatbelt tensioning (tightens seatbelts prior to impact), and sandwich platforms (allows the engine to slide under the occupants in a head-on collision).

In the event an accident results in a rollover, the PRE-SAFE feature unlocks the doors and lowers the windows approximately 1 cm (1⁄2 in) to allow you to exit or safety workers to gain access easily.

Features include the capability to withstand small arms fire and certain explosive devices, a self-sealing fuel tank, and an alarm system.

Founded by Daimler Motoren Gesellschaft in 1915, the Sindelfingen plant also produced the model 600 "Grosser Mercedes" and past generations of the S-Class.