Approaching a corner on Route 1 just north of Stinson Beach, California, I see a man dart across the road in order to crouch in the tall grass on the opposite shoulder and aim a camera my way. Just as my 2019 Mercedes-AMG E 53 bends into the curve, the car’s Pre Safe technology activates, cinching me tight enough to the driver’s seat to take my breath away. After several seconds, the seat belt relaxes, leaving me shaken and not stirred.
Later, while talking with Brian Cotter, Product Manager for Mercedes-AMG, we’re trying to determine why Pre Safe suddenly and unexpectedly engaged. The only possible explanation is that the system detected either the photographer, or the cliff just behind the photographer, or the Mercedes-Benz GLS the photographer had parked on the right shoulder of the road (or all three) and determined that a crash was imminent.
In this case, Pre Safe engaged when it wasn’t necessary, highlighting two important points:
- It is good to have such systems when they’re necessary.
- Sometimes the technology is inaccurate.
What is Included in the Mercedes Driver Assistance Package?
Pre Safe is just one of numerous occupant safety technologies and advanced driver assistance systems (ADAS) available for 2019 Mercedes-Benz models. Some of them, like Pre Safe, are standard equipment. Most, however, are options offered as separate upgrades or bundled into packages.
With regard to the E-Class, the Driver Assistance Package ($2,250) is the option to choose for the maximum technological benefit. It contains 14 different features that enhance the car’s safety, and I got a chance to experience all of them during a test drive of an AMG E 53.
When you opt for the Driver Assistance Package, you get the following upgrades:
Active Distance Assist Distronic with Extended Restart – Adaptive cruise control that maintains a safe distance behind traffic ahead, can bring the car to a stop, and in stop-and-go traffic will automatically resume within 30 seconds.
Active Steering Assist – In conjunction with Distronic, this centers the car in the lane of travel and can follow vehicles ahead when lane markings are unclear or unavailable.
Active Blind Spot Assist – Discourages a driver from changing lanes if another vehicle is in the blind spot by selectively braking the wheels to tug the Mercedes back into its lane.
Active Lane Keeping Assist – Selectively brakes the wheels to help prevent the Mercedes from drifting out of the intended lane of travel.
Active Lane Change Assist – In conjunction with Distronic, this feature helps to change lanes and overtake slower traffic when the driver signals and it is safe to do so.
Active Brake Assist with Cross-Traffic Function – Monitors for vehicles and pedestrians ahead. If a car drives in front of the Mercedes, the system emits a warning. When the driver brakes in response to that warning, the system provides the necessary amount of braking to prevent an impact or reduce its severity. If a pedestrian walks in front of the Mercedes, the automatic emergency braking system will engage.
Active Emergency Stop Assist – In conjunction with Distronic, if a driver falls asleep or suffers a medical emergency, this system can bring the Mercedes to a staged stop, activate the hazard flashers, and place an emergency SOS call to get help.
Active Speed Limit Assist – In conjunction with Distronic, this system reads speed limit signs and adjusts vehicle speed accordingly.
Evasive Steering Assist – Offers an added measure of safety when the driver makes a sudden evasive steering maneuver.
Congestion Emergency Braking – When traffic ahead comes to a sudden stop, this system can assess whether or not a driver has a way around the congestion and, if not, automatically engages the emergency braking system.
Pre Safe Plus – Works similar to Pre Safe, but prepares the vehicle’s cabin and its occupants for a rear instead of a forward collision.
Pre Safe Impulse Side – When another vehicle is about to crash into the Mercedes on the side, this system inflates air chambers within the door-side of the seat. This moves the occupant toward the center of the vehicle in order to reduce the potential for injury.
Route-based Speed Adaptation – In conjunction with Distronic, this automatically reduces vehicle speed based on the navigation system’s map database and the ADAS technology, slowing as the vehicle approaches exits, curves in the road, roundabouts, tollbooths, and more.
Look Ma! No Hands!
During drives in both a 2019 Mercedes-AMG CLS 53 and an E 53 Sedan, I was able to sample several of latest ADAS technologies from Mercedes-Benz in a variety of driving scenarios.
Cotter told me that Distronic’s Active Steering Assist works better when the system can follow a vehicle ahead, and I would agree. On freeways leading out of San Francisco, the CLS 53 tracked true in the center of the lane, faithfully following gentle bends and maintaining a proper distance from the car ahead. On country two-lane roads, the system behaved in a more cautious manner, sometimes allowing the car to wander within the lane.
Regardless of the driving environment, if you remove your hands from the steering wheel, Active Steering Assist will ultimately request that the driver place his or her hands back on the steering wheel. This can happen within seconds, or it can take a minute or two. The bottom line is that this technology supports rather than replaces a driver.
On one flat, straight, empty stretch of road, I decided to see what would happen if I ignored Active Steering Assist’s pleas to put my hands back on the steering wheel. After repeated warnings, the car initiated an Active Emergency Stop Assist.
This technology works when Distronic is engaged and assumes that a driver is either asleep or has suffered a medical emergency. In stages, it will bring the Mercedes to a stop in its lane of travel, activate the hazard flashers, place an emergency SOS call, and unlock the doors to make it easy for first responders to help the driver. Obviously, I didn’t need to experience any of this first-hand, so I gripped the steering wheel and deactivated the Active Emergency Stop Assist.
Driving California Route 1 south from Valley Ford, the speed limit is 55 mph except in the many small towns that dot the coastline. Often, drivers will get a single warning sign that the speed limit is going to change, and then suddenly you’ve entered a 35-mph or 25-mph zone.
Mercedes says that its Active Speed Limit Assist system is updated to proactively adjust the car’s velocity ahead of reduced speed zones, but that was not my experience in the E 53. It remained pegged at 60 mph until I passed the 35-mph or 25-mph speed limit sign, and then would slow down. Luckily, I didn’t get any tickets.
On the other end of these idyllic hamlets, a sign would signal the end of the reduced speed zone. Yet the E 53, presumably, would not accelerate back to 60 mph until it found another speed limit sign to read.
Given that a route was pre-programmed into the E 53’s navigation system, you’d think the car would know the speed limit based on the map database. It certainly was able to determine when it was unsafe to take a corner at my set speed of 60 mph, automatically slowing to a more advisable pace, but did not behave in a predictive manner entering or exiting towns.
Later, as I crossed the Golden Gate Bridge into San Francisco, the Route-based Speed Adaptation technology rightly predicted that the E 53 was approaching a tollbooth, and slowed the car to 25 mph. This, in turn, got me a middle finger from the impatient motorist behind me.
Welcome to San Francisco.
Mercedes Engineers Effective ADAS Technologies
Groggy drivers will like the Active Lane Keeping Assist technology. It vibrates the steering wheel to notify the driver when the Mercedes is drifting out of its lane, and if you don’t respond it can selectively brake individual wheels to bring the car back into the intended lane of travel.
At some point, I activated both the vibration and the braking. I was driving on a two-lane road, and I was probably trying to determine why, for the umpteenth time, the navigation system was asking me if I wanted to cancel my route. (I think I kept brushing my wrist across the wrong part of the infotainment system’s touch-sensing COMAND module on the center console.)
In any case, the wheel vibrated and then the E 53’s braking system kicked in, tugging the car back onto the right side of the double yellow lines. It is an effective tool.
If you don’t want to use the Active Steering Assist and Active Lane Keeping Assist systems, Mercedes makes it easy to shut them off. Just push the buttons on the dashboard to the left of the steering wheel.
As for the Active Distance Assist Distronic adaptive cruise control, well, that’s the only version available. There is no basic cruise function, like you’ll find in some vehicles. With the Mercedes, you use it or you drive the car all by yourself.
Given how effective Distronic is, and how much fun the CLS 53 and E 53 are to drive, either way is just fine by me.
Just watch the road ahead for wildlife. Or photographers.