Highway Autopilot in Real Life: What Today's Systems Can Actually Do

Level 2+ or Level 3: what does that actually mean on a real highway drive? A hands-on test shows how far BMW's highway assistant and the Mercedes Drive Pilot really go, and where both systems hit a hard wall.

Between Assistance and Real Autonomy

Few terms get thrown around as loosely at car dealerships as "autopilot." Order a new BMW 5 Series or a Mercedes EQS today, and you get systems that behave with surprising independence on the highway: they hold their lane, pass slower traffic, change lanes, and react to the flow around them. Yet technically and legally, these two cars live in completely different worlds. The reason comes down to the SAE levels, the framework that defines exactly how much responsibility a machine is allowed to take on and how much stays with the human behind the wheel. Once you understand the five SAE levels of autonomous driving, it becomes obvious why a marketing term like "autopilot" is often more branding than substance.

For EV shoppers, this distinction matters more than it might seem, because many of the most advanced driver-assistance systems debut first in electric or plug-in models, and because they directly shape what a long highway stretch feels like. How relaxed is the drive to the next fast charger if the car is handling part of the driving task for you? That is exactly the question a recent real-world comparison set out to answer, pitting BMW's highway assistant against the Mercedes Drive Pilot under everyday driving conditions. Before diving into the results, it helps to understand the basic difference between conventional driver-assistance systems and genuine self-driving technology, because that distinction ultimately decides who actually has to keep their eyes on the road.

Source: ADAC: Wie autonom fahren 5er BMW und Mercedes EQS tatsächlich?

The Real-World Test: Two Philosophies, Two Levels

Side by side, it quickly becomes clear that BMW and Mercedes take deliberately different approaches to highway autopilot. The test ran on real highway sections with mixed traffic, varying speeds, and changing weather, exactly the everyday conditions that matter most to buyers. One automaker leans on a highly developed assistance system that still leaves the driver fully responsible under the law. The other became the first manufacturer, in Germany, to hand real legal responsibility to the machine itself, though only inside a very narrow operating window.

BMW 5 Series: Level 2+ with an Impressive Range of Features

The highway assistant in the BMW 5 Series operates at Level 2+, a highly advanced form of driver assistance. Up to speeds of about 80 mph, the system reliably handles a long list of tasks without the driver needing to intervene manually. In testing, that included:

• Automatic lane changes when the adjacent lane is clear
• Independent passing of slower vehicles
• Autonomously exiting the highway at a pre-programmed exit
• Speed and distance control in heavy traffic
• Continuous lane centering through curves and construction zones

The key point, though, is the legal classification: even though the system handles a great deal on its own, the driver remains fully responsible for what happens on the road. An interior camera continuously checks that the driver's eyes stay on the road, because at Level 2+, hands-free explicitly does not mean eyes-free. In testing, if the camera flags a warning and the driver doesn't respond within a few seconds, the car noticeably slows down and signals, both audibly and visually, that the driver needs to take back control. For a closer look at how German automakers are positioned on this front, see how BMW, Audi, and VW are approaching self-driving technology.

Mercedes EQS with Drive Pilot: Level 3 Under Strict Conditions

The Mercedes EQS with Drive Pilot takes a fundamentally different approach. In Germany, it became the first Level 3 system certified by regulators back in 2021, and it genuinely lets the driver take their hands and eyes off the road to do other things, as long as certain conditions are met. That is the fundamental difference from the BMW system: within this narrow window, the machine, not the human, carries the legal responsibility.

That window, however, is far tighter than most people expect. The real-world test made clear just how many restrictions apply to Drive Pilot:

• Maximum speed of about 60 mph
• A vehicle ahead is required as a reference point
• Cannot be used in rain or on wet roads
• Cannot be used after dark
• Cannot be used inside tunnels
• Deactivates below roughly 39°F outside temperature

In practice, that meant the Mercedes in the test never ran fully autonomously for more than about ten minutes at a stretch before the driver had to take back control, whether because the car ahead changed lanes or a weather condition no longer qualified. Still, those short but genuine stretches were enough to feel the difference: the driver could read, check their phone, or simply lean back while the system took full control. For a deeper dive into this system, see our full breakdown of Mercedes Drive Pilot as Germany's first Level 3 autopilot.

Sensors Compared: Why the Technology Differs So Much

The gap between the two systems' capabilities comes down directly to the sensors each one carries. BMW's highway assistant relies on a combination of cameras, radar, and navigation data, which is sufficient for a Level 2+ system that still requires driver supervision. Mercedes equips the EQS for Drive Pilot far more heavily, adding lidar, ultrasonic sensors, a rear-facing camera, microphones to detect emergency vehicles, moisture sensors, and specialized high-resolution map data. That extra layer of lidar, radar, and camera sensing is the actual reason Drive Pilot could be approved to take on legal responsibility in the first place, even though that same heavy redundancy is exactly why its operating window stays so narrow. The more redundant sensor sources a system has, the more reliably it can spot edge cases before they turn critical, and the more responsibility regulators are willing to let it carry.

What This Means for Everyday Driving and the Road Ahead

The test drives home one point clearly: the gap between Level 2+ and Level 3 isn't just a technical footnote, it fundamentally changes what driving feels like. Level 2+ remains supervision-required no matter how automated it feels, while Level 3 genuinely runs supervision-free within its narrow conditions. For buyers, that means anyone hoping to truly switch off during long, relaxed highway stretches will currently only get that experience in a fairly limited set of scenarios, such as stop-and-go traffic or moderate highway speeds in dry daylight conditions.

Over the long run, it's reasonable to expect the operating envelope for systems like Drive Pilot to expand step by step: higher speed limits, more weather conditions, and eventually the ability to operate without a lead vehicle as a reference point all look like realistic next steps. Meanwhile, other automakers are working toward their own Level 3 approvals, so competition in this space is likely to intensify over the next few years. For a broader view of how this plays out globally, our comparison of China, the US, and Europe in the race for self-driving technology shows that while Germany took an early lead on Level 3 certification, other regions are pushing much further ahead with robotaxis and Level 4 deployments.

One often-overlooked question is liability if something goes wrong. As long as a system like BMW's highway assistant operates at Level 2+, liability stays with the driver. Only with a genuine Level 3 system like Drive Pilot does that responsibility shift to the manufacturer, and only under the approved operating conditions. The legal nuances here are complex and are explained in more depth in our guide to who is liable in a self-driving car accident.

It's also worth zooming out to the bigger EV picture: assistance systems that reliably hold a lane and manage following distance make long stretches between charging stops noticeably less draining, something that becomes especially clear on long-distance EV road trips. Arriving at a fast charger after several hours on the highway feels a lot less exhausting when part of the lane-keeping and distance management has been handled by the car along the way. For many EV shoppers, that reduced fatigue is a genuine, practical reason to buy, even if the word "autopilot" itself tends to oversell what's actually happening under the hood.

For now, the takeaway is that both systems showcase genuinely impressive technology, but each within clearly defined boundaries. Anyone buying a car with a highway assistant today should understand its real capabilities and limits rather than relying on marketing language. That practical knowledge is ultimately what determines how safe, and how relaxed, everyday highway driving actually feels.

Additional Video

For a broader perspective beyond a single automaker, this Edmunds comparison puts Tesla, BMW, Ford, and GM hands-free highway systems side by side to show how today's real-world driver-assist tech actually stacks up across brands.

Source: Edmunds Cars – (Almost) Self-Driving Car Comparison Test: Tesla vs. BMW vs. Ford vs. GM | Hands-Free Driving Test