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2014 Mercedes-Benz S550 review: New S-Class takes the lead with self-driving tech

The 2014 S550 is an automotive tech juggernaut, featuring every latest advance Mercedes-Benz could develop; it's even capable of steering itself.

Wayne Cunningham Managing Editor / Roadshow
Wayne Cunningham reviews cars and writes about automotive technology for CNET's Roadshow. Prior to the automotive beat, he covered spyware, Web building technologies, and computer hardware. He began covering technology and the Web in 1994 as an editor of The Net magazine.
Wayne Cunningham
12 min read

As I drove the 2014 Mercedes-Benz S550 for this review, a number of nicknames came to mind. Because of its sheer comfort and luxury, I was thinking Chariot of the Gods. The utter blackness of the paint and subtle exterior lines suggested Death Star. While powering along a twisty mountain road, it also seemed the perfect car to pack full of villains and go after James Bond in his Aston Martin in, so Anonymous Baddie Car, maybe.

2014 Mercedes-Benz S550

2014 Mercedes-Benz S550

The Good

Mammoth cabin space and smooth ride quality make the <b>2014 Mercedes-Benz S550</b>'s cabin the place to be, whether in front or back. LED lights and big LCD dashboard panels keep the tech ahead of the pack. A new Steering Assist feature eases driving in heavy traffic.

The Bad

App integration loads too slowly for general use. Virtual instrument gauges look a little flat, and it needs a graphic fuel gauge.

The Bottom Line

Mercedes-Benz takes a big step forward with its 2014 S550 flagship sedan, improving just about every feature in this model update, but app integration suffers from slow connection times.

Given its size (over 17 feet), powerful engine, and loads of tech, it is certainly worthy of more than one nickname.

Mercedes-Benz's flagship S-Class luxury sedan has been facing stiff competition, from the Audi A8 to even the Hyundai Equus. The company obviously couldn't rest on its laurels, especially considering the much lower prices of a few other big, luxury rollers.

2014 Mercedes-Benz S550 showcases superluxury (pictures)

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The 2014 S550 shows that Mercedes-Benz took the threat seriously, and designed a car that will force other luxury sedan makers back to their drawing boards. Along with redesigned bodywork, a huge cabin, large LCD panels for instruments and cabin tech, and fuel economy technology, Mercedes-Benz adds an innovative steering-assistance feature that will ease driving and bring the S550 one step closer to being an autonomous car.

Dark and sinister
The phrase "understated elegance" seems crafted specifically for the S550's body. Despite a wide silver grille dominating the front, the skin lacks ornamentation or embellishment. It is an incredibly clean look. That look, despite the shape being nothing like a small moon, is what made me think Death Star would be an appropriate name. And while a few drivers gave me a thumbs-up as I drove by, more seemed to find the big, black sedan sinister, and pulled off the road to let me by.

Planting a flag in the future, Mercedes-Benz brags that the S550 does not have a single incandescent bulb -- from headlights to cabin lights to taillights, all illumination comes from LEDs.

2014 Mercedes-Benz S550
The S550's bodywork may be subtle, but its impact certainly isn't. Josh Miller/CNET

The first S-Class models to hit showrooms all come standard with a long wheelbase, meaning an incredibly spacious rear seating area. None of your passengers will be calling shotgun, and you might make a habit of letting friends drive, so you can lounge in back. Those rear seats are power-adjustable, with comfy suede pillows attached to their headrests, and a dedicated sunroof overhead.

The front seats had the bulk and surface area of living-room recliners. Among the seven different massage settings, there were a couple that combined the seat heating function with the internal rollers. The seat adjustment controls were mounted on the doors, one ergonomic nicety I've always appreciated about Mercedes-Benz. For an over-the-top feature, the glove compartment held a scent container, a kind of aromatherapy system for the cabin.

From front to back, the S550 felt like a worthy Chariot of the Gods.

Wide-screen times two
Mercedes-Benz embraces advanced technology in the cabin, the most obvious sign being the two immense LCD panels on the dashboard. Sure, the previous S550 had an LCD at the center of the dashboard for navigation and other cabin tech features, but this 2014 model goes jumbo, having a center screen that looks about a foot wide. This LCD shows Mercedes-Benz's standard Comand interface, using menu strips across the top and bottom, but all the screens have been redesigned, updating the look and information layout.

2014 Mercedes-Benz S550
The virtual instrument cluster rendering is a little flat, but the LCD allows a lot of different information for the driver. Josh Miller/CNET

In front of the driver, Mercedes-Benz does away with analog gauges in favor of a full LCD instrument cluster. I like this move, but the virtual speedometer and tachometer could use some refinement. I've seen some virtual gauges that were difficult to tell from the real thing, but the ones in the S550 look a little flat. I also didn't like the fuel level indicator, merely a percentage of fuel remaining showing at the bottom of the speedometer. Mercedes-Benz could have splurged on a more graphic representation of the fuel level.

Not much has changed with the underlying cabin tech features, and that is a good thing. Mercedes-Benz takes advantage of the big main LCD to show well-rendered maps, complete with 3D buildings. The large size of the screen made it easy for me to pick up details at a glance, such as traffic flow. And the map even showed which intersections had traffic lights.

Under route guidance, the S550 did an excellent job of giving me turn directions. Not only did the voice prompts read out street names and give good advance warning for turns, the screen graphics included lane guidance and good representations of freeway junctions. On top of that, the dynamic routing seamlessly recalculated to keep me out of more than one bad traffic situation.

Address entry used the same scheme as in the previous S550 model -- I had to turn the Comand interface's rotary dial to tediously scroll through the alphabet and pick letters. However, the response time was quick and the system had predictive entry, which gave me a list of all possible results depending on which letters I had chosen. Think of it as a good version of autocorrect.

2014 Mercedes-Benz S550
The massive center LCD shows detailed 3D maps for navigation, with excellent route guidance graphics. Wayne Cunningham/CNET

Better yet, Mercedes-Benz has finally updated its voice command system, so that I could say an entire address string and the system would parse city, street name, and number. Voice command also gave me detailed control over the stereo, letting me request music by artist or album name from a drive or iOS device I had plugged into one of the S550's two USB ports. As in other Mercedes-Benz models, I could also place calls by saying a contact name from my Bluetooth-paired phone.

Other audio sources included HD Radio, Bluetooth streaming, the onboard hard drive, a six-CD changer, and, new for Mercedes-Benz, the TuneIn Internet radio app. I liked the new music library screens, which included an option for choosing albums by cover art.

For another luxury touch, Mercedes-Benz gives the S550 a Burmester audio system, standard. The car I reviewed was upgraded to a Burmester surround-sound system, and had very attractive aluminum speaker grilles. The audio quality was incredibly detailed and balanced. Listening to acoustic tracks by The Civil Wars, I could hear the individual vibrations of guitar strings, clear from attack to sustain. Fiddling around the three-band equalizer, I pumped the bass and got a convincing thump that palpably shook the air in the cabin. As I raised the volume, the music became more enjoyable rather than distorted.

TuneIn radio, part of the Mercedes-Benz Apps library, was the most successful portion of this connected feature. I recently reviewed the Mercedes-Benz GLK250, and found that Mercedes-Benz Apps took too long to connect to be useful. In this car that still went for apps such as Google Search and Facebook, but I tend to keep a music app like TuneIn running for a while, so the extended load time was a smaller percentage of my use of the app. TuneIn let me dig up online radio stations from around the world and play them through the car's stereo. For the S550, Mercedes-Benz has added more apps than in other cars with this feature, but it won't be really successful until the company addresses the load times.

2014 Mercedes-Benz S550
TuneIn radio app integration lets you find online radio stations from all over the world. Wayne Cunningham/CNET

It would also be nice to see Pandora in the mix, as it has become widely adopted among other carmakers.

Take the reins
All of this cabin tech seemed like a lot to handle, but the S550 was there to help with the driving. Mercedes-Benz pioneered adaptive cruise control with an earlier generation of its S-Class, and now adds a near-autonomous feature, Steering Assist. Adaptive cruise relies on radar to detect the speed of any cars ahead, and match that speed if it is slower than what you set for cruise control. I have driven literally hundreds of miles at a stretch without touching gas or brake pedals using adaptive cruise control.

Steering Assist is a new wrinkle on adaptive cruise control. The S550 had stereoscopic cameras mounted up on the windshield, in front of the rearview mirror. These cameras let the car know the location of lane lines. When I activated the adaptive cruise control system, the car not only matched the speed of slower traffic ahead, but tried to hold its position in the lane, actively steering the wheel to compensate for curves.

2014 Mercedes-Benz S550
Along with radar mounted in the grille, the S550 features stereoscopic cameras in front of the rearview mirror. Josh Miller/CNET

Using Steering Assist reminded me of an anecdote about a milkman who began his delivery career with a horse and cart. He would jump off the cart, grab a rack of bottles, then go down an alley between a block of houses putting bottles down at each door. Meanwhile, the horse plodded on down the main street of its own accord, meeting the milkman at the end of the block. When the milkman traded in horse and car for a truck, he had to continually park, deliver the milk, then go back to the truck and drive down a few more houses. Lather, rinse, repeat.

The S550 wasn't as smart as the old delivery horse, but its sensors could see the road, and holding the wheel seemed like using reins to guide a horse.

At speed down the freeway, Steering Assist wasn't robust enough to keep the car in its lane without my help, and the car gave me a warning when I took my hands off the wheel. However, up to speeds of 18 mph, Mercedes-Benz says the system will keep you in your lane and won't bother you about keeping your hands on the wheel.

I was only in one, short traffic situation slow enough to test it, but, putting my faith in German engineering, I let go the wheel and was suitably impressed how the car drove itself.

2014 Mercedes-Benz S550
The instrument cluster changes to this screen when adaptive cruise control is active, showing when slower traffic is ahead. Josh Miller/CNET

One caveat, the system only works when the cameras can distinguish lane lines. A little steering-wheel icon turns green when the car meets that condition. I had to monitor that icon because, given often bad roadwork, it frequently wasn't able to get a lock on the lines.

Mercedes-Benz makes a raft of other driver assistance features available on the S550, including a night vision system. This model came with a blind-spot monitor, which flashed icons in the side mirrors when it wasn't safe to change lanes. Blind-spot monitors are one of my favorite safety features, and very helpful in the big S550. The backup camera also showed incredibly sharp detail, and the large LCD made possible a gigantic image, complete with trajectory lines to aid parking.

Eco or Sport
When I turned off cruise control and asserted full control of the S550, I found it an easy cruiser but tense when pushed. With 455 horsepower and 516 pound-feet of torque, the engine gives this big sedan more than enough push. Like Mercedes-Benz' other 550-designated models, the S550 gets a 4.6-liter V-8, which uses direct injection and twin turbos for efficiency and boost.

At the time of this review, Mercedes-Benz had not released the car's curb weight, but it puts the zero-to-60 mph time at 4.8 seconds, very respectable for this big roller.

2014 Mercedes-Benz S550
The S-E button toggles the car from Sport to Eco, and the Sport-Comfort button changes the air suspension setting. Wayne Cunningham/CNET

I appreciated how Mercedes-Benz kept the drive modes simple. The S550 is either in Eco or Sport, because why would you need any more granularity? An extra button adjusts the air suspension between Comfort and Sport, the former making it feel as if the car floats over potholes and bumps.

Around town and on the freeway, I left it in Eco mode, which softened the accelerator response, making it easier to creep in traffic and make sedate starts off the line that wouldn't jostle my passengers' cappuccinos. In this mode, stamping the gas pedal made it feel as if the car had to gather its power up before it would unleash it all with locomotivelike power.

The seven-speed automatic transmission shifted seamlessly through the gears, seeking the highest available for the speed. Whenever I glanced at the virtual tachometer, it sat at 1,500rpm, whether I was cruising city streets at 20 mph or barreling down the freeway at 70.

The electrically boosted power steering offered little resistance, making for easy maneuvering but numb response. Despite the huge cabin area, the S550 felt like a smaller car as I cut through traffic, taking advantage of openings for quick lane changes.

2014 Mercedes-Benz S550
The S550's turbocharged 4.6-liter V-8 produces plenty of power for the big sedan, and runs quietly. Josh Miller/CNET

Impressively, the S550's idle-stop feature wasn't annoying. Idle-stop shuts the engine down when you stop at a red light, and rival manufacturer BMW has had a difficult time making that feature work smoothly in its larger engine cars. In the S550, the engine generally runs so quietly that I had to check the tachometer to see when it was actually stopped. As I lifted off the brake pedal, the engine restarted with the gentleness of a small-displacement four-cylinder. I was able to turn off idle-stop at the touch of a button, but I found no need, and appreciated that the big V-8 wasn't burning gas as I sat for minutes at red lights.

As for fuel economy, Mercedes-Benz didn't have its official EPA numbers by the time of this review. The trip computer showed mid-20s on the freeway and high-teens in the city, about what I would expect. My average, including freeway, city, and some raucous back-road driving, came in at 18.2 mpg.

With the S550's engine and suspension in Sport modes, it transforms into that Anonymous Baddie Car for chasing down James Bond. And showing a good sense of place, it wouldn't likely run him down. Nimble is not a word I would use for the S550, and it wouldn't be my first choice for racing through the bends on a good road.

It handled high speed decently, but the air suspension, even in Sport mode, couldn't keep it flat in the turns. Mercedes-Benz offers an option called Magic Body Control, not equipped on the car I tested, which not only exerts more active suspension response in the turns, but uses the car's cameras to analyze the road surface and respond with an appropriate ride program. That option might make the car handle tight turns better and contribute to an even more comfortable ride.

2014 Mercedes-Benz S550
Heavily boosted electric power steering makes the wheel very easy to turn. Josh Miller/CNET

Putting the engine in Sport mode made the gas pedal almost too responsive. My smallest input led to surges of power, unexpected considering the much more docile Eco performance. Personally, I would like the Sport response toned down just a bit, but your average James Bond-chasing villain may prefer the more sensitive pedal.

The transmission also takes on a different character in Sport mode, letting the tachometer needle run rampant around its dial. I was impressed when, braking heavily before a corner, the transmission geared down quickly, then held the engine at a solid 4,500rpm as I made the turn exit.

The S550 came equipped with paddle shifters on the steering wheel, and the transmission allowed quick manual shifts. However, I could not find a means of keeping the car in manual mode. Whenever I left the paddles untouched for a couple of minutes, such as on a straight, the transmission switched back to automatic shifting.

A bold step forward
With the 2014 S550, Mercedes-Benz shows what a flagship sedan should be. This car debuts new technologies and plants the Mercedes-Benz marque firmly in the future. Impressively, Mercedes-Benz doesn't coddle older buyers who might feel uncomfortable with virtual gauges, LED lighting, and near-autonomous features, instead implementing available advances that improve driving comfort and safety.

Steering Assist may seem radical, but it represents the same type of step forward Mercedes-Benz made previously with its Distronic Plus adaptive cruise control.

The tech features in the new S550 are almost too numerous to mention, and most are implemented successfully. The massive center LCD makes cabin tech features less distracting, as well-designed screens make it easy to pick up information at a glance. The LCD instrument cluster could use a better 3D look, but it represents the wave of the future for cars.

Fuel economy may be middling, but the S550's engine shows off a good set of modern efficiency and power technologies, and its seven-speed automatic transmission responded well in both Eco and Sport modes. Mercedes-Benz also implemented an idle-stop feature worthy of the company's luxury brand.

Navigation and audio systems are also top-notch, and the Burmester audio system is a delight to the ears. App integration remains the one weak spot in this technology cornucopia. Mercedes-Benz gave the S550 more apps than on its previous models, but the company needs to negotiate a better, always-on data connection for the car.

Tech specs
Model 2014 Mercedes-Benz S550
Trim Base
Power train Turbocharged direct-injection 4.6-liter V-8, 7-speed automatic transmission
EPA fuel economy Not available
Observed fuel economy 18.2 mpg
Navigation Standard hard-drive-based system with traffic
Bluetooth phone support Standard with contact list integration
Digital audio sources Internet-based radio, onboard hard drive, Bluetooth streaming, iOS integration, USB drive, SD card, HD Radio, satellite radio
Audio system Burmester system
Driver aids Optional adaptive cruise control with steering assistance, blind-spot monitor, backup camera, night vision, surround-view camera, lane-keeping assistance, massage seats
Base price Not available at time of review
Price as tested Not available at time of review
2014 Mercedes-Benz S550

2014 Mercedes-Benz S550

Score Breakdown

Cabin tech 10Performance tech 8Design 9


See full specs Trim levels S550Available Engine GasBody style Sedan