Our first opportunity to get into the fourth-generation Audi A8 came with an offbeat premise: We’d be heading out into what Audi boasts is the second most traffic-choked area in the whole of Europe, near the German cities of Essen and Düsseldorf—and we’d be doing so with the hope of getting stuck in traffic.
This isn’t a true first drive of the 2019 Audi A8, but it was our first opportunity to gain an understanding of how a new feature in the A8 works on a congested highway. Called Traffic Jam Pilot, it’s been specifically developed for SAE Level 3 automated driving—meaning that the driver no longer has to monitor the surroundings continuously and that the vehicle system will alert the driver when he or she needs to retake control. Audi claims it’s a world first.
There’s a big asterisk next to what we describe, because we weren’t in the driver’s seat. Whether in Germany or back in the United States, for Level 3 automated driving a specially certified test engineer must be ready to take over. In our case, that was Peter Bergmiller, technical project lead for the system.
Part Traffic Hunter, Part Road-Trip Bingo
“I think we might get lucky!” Bergmiller exclaimed excitedly, homing in on a red-colored stretch of motorway on the navigation system’s live-traffic maps and anticipating that there was about a mile-long traffic jam up ahead. Soon we were in a sea of brake lights, and as our speed fell below 37 mph (60 km/h), the dash display showed a vehicle within white markings, signaling that the system was ready to take over. Bergmiller simply pressed the Auto AI button at the far front of the center console and pulled his feet and hands away from the controls. The A8 was driving itself until further notice.
For now, Traffic Jam Pilot only engages if the system can meet a checklist of parameters. It has to to be on a limited-access divided highway; it needs to have a vehicle directly in front and a line of slow-moving vehicles in adjacent lanes; and the system needs to be able to make out lane markings and the edge of the roadway (with a barrier or guardrails, for instance).
The system is designed to keep doing the driving even if it momentarily can’t follow roadway markings, pointed out Bergmiller. That may not be a situation you’d find in Germany. It is more likely in the U.S., where lane markings are “of varying quality, we’ll leave it at that,” he quipped.
“A Level 3 system takes the responsibility of the driving task, so we also had to change the way you use it,” he explained. “It’s no longer like with the classic driver-assist systems where you just activate the system and whenever it can do something, it does.”
Bergmiller made a few quick menu selections on Audi’s MMI and brought up the pan-European TV channel Arte—pointing out that once the system is engaged it’s entirely fine for the driver to watch TV, respond to text messages, or have a face-to-face conversation with a passenger. Under Level 3 conventions, the driver can take his or her focus away from the road, but only to use entertainment or productivity features that are fully integrated with the vehicle’s interface.
Barely a minute goes by before there’s a warning chime and a visual prompt for Bergmiller to retake control—because we’re leaving the autobahn and transitioning to a divided highway with occasional traffic lights.
No Napping in the Driver’s Seat
Strict rules still apply to the driver, who must remain with butt in seat and torso pointing forward. Infrared sensors and a camera study eye movements and head motions, respectively, to assure alertness for when Traffic Jam Pilot makes a transition request to have the driver retake the wheel. Once you’ve been caught snoozing, the system can’t be enabled again until after you stop.
On the handoff back, the driver is expected, ideally, to take over within 10 seconds, in response to a chime and a pulsating red reminder at the edges of the Virtual Cockpit display. Beyond that, the request gets more audibly and visibly urgent as the car turns down the audio system and jerks the seatbelts in a not at all subtle way. Go no-hands past the 20-second mark and the car will follow an escalation strategy, starting to decelerate, activating its hazard lights, and slowing down within the lane of travel, then unlocking the doors and calling for emergency assistance as it rolls to a stop.
Traffic Assist Pilot gets some of the data it uses remotely—such as map data and routing information (it even adapts its driving behavior to local rules)—but it doesn’t rely on over-the-air connections for anything safety critical. All the sensing and decision making is done onboard, with a suite of hardware that includes 12 ultrasonic sensors, four 360-degree cameras, one single-lens front camera, four midrange radar sensors, one long-range radar sensor, and a forward laser scanner.
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“Your phone may just crash and restart. This is not an option for the system in a decision to brake or not brake.”
– Peter Bergmiller, Audi
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Bergmiller emphasized that the team put a tremendous effort into the platform of the vehicle, so it would be very hard to upgrade items such as actuators and brakes part way through the model’s life cycle. All the controllers and actuators are capable of handling the car at the limit—a requirement that essentially sent the A8 through two separate development paths.
Over an extended lunch stop, we learned more about the processing that gathers all those inputs, makes decisions, controls the vehicle, and even anticipates the future. Each of those sensors has its own strengths and weaknesses (radar is good for seeing two cars ahead, for instance). So inputs are processed individually at the sensor level and then factored together, within a central controller (which Audi calls zFAS), into a complex “sensor fusion” processing to paint a picture of what’s around the vehicle. A second sensor fusion is processed in a different location in the vehicle, with the laser controller, and then the ordered tasks from the two paths are checked. “If one of these two paths says that we have to hit the brakes, this is supercritical, we just do it and go the safe way,” said Bergmiller. “The safer action always wins.”
Thinking Ahead
The A8 we drove might have been badged Audi Intelligence, but here’s where a different kind of AI (artificial intelligence) comes in. One sensor fusion uses a time-triggered processing path—meaning it can disregard sensor inputs that probably aren’t critical at the moment (learning and prioritizing as it goes) in order to cycle through its operations once every 40 milliseconds—while the other one processes through all the sensor inputs.
The system is always, in parallel, predicting the future position of everything for at least four seconds, according to Bergmiller. “So if all the sensors were to go blind, we have this knowledge about the future that we had been predicting right before that, and we can send that information to the brake system,” he said. “Every input from every sensor arrives at the processor with a time stamp from milliseconds in the past, so a certain amount of prediction is necessary in nearly every calculation within automated driving.”
It can’t be emphasized enough that having the driving computers crash, lag, or reboot is absolutely unacceptable. “Your phone may just crash and restart,” said Bergmiller, with a serious expression. “This is not an option for the system in a decision to brake or not brake.”
On the other hand, a concern that does carry over from personal devices—perhaps even more so—is data security. By German privacy law, Audi isn’t allowed to store any personal or vehicle data without a key safety reason behind it. Cars with Traffic Jam Pilot get what’s effectively a black box that can allow retrieval of data only about how the vehicle sees the world and whether or not the driver was in charge at the time of the accident. No images of the driver or the environment are stored, and all data belongs to the driver, who must visit a dealership and sign paperwork to decrypt that data.
Software upgrades are easily done, but, for security reasons, Audi does not want over-the-air updates yet; any updates would be administered at the dealership via a secured and encrypted connection.
Fine Print and Legalese
In the United States, Audi is hoping to keep to a similar privacy standard, but things are likely to be a bit different. As Audi of America put it, the federal government regulates the car, while the states oversee the driver and the observance of traffic laws. Traffic Jam Pilot currently isn’t allowed in any of Audi’s markets without special allowances, such as having this test engineer behind the wheel. Officials are optimistic that in Europe and the U.S. it will soon be allowed—so optimistic that they hope to simply start building the complete hardware set into all A8 models within the next year or so.
Although Audi thinks of Level 4 automated driving—which would always offer to take the wheel in certain situations, such as on the highway or in a parking garage—as being some years off, there’s potential to expand this Level 3 technology. With the current hardware, for the most part, Audi could extend the A8’s Level 3 capability to non-limited-access divided highways or to higher freeway speeds—up to 81 mph, potentially—although Bergmiller hints that would take a predictive window well beyond the current four seconds, plus more rigorous expectations in handing control back to the driver. Lane-change functionality could be another forward step.
Eventually we got a short stint with Traffic Jam Pilot (and the A8) from the driver’s seat—on a closed course, with a chase car and some special programming—where we found the system resilient and flexible in the way it takes control, as well as far smoother in its inputs than current lane-keeping aids. We were invited to try other things that might also prompt the driver for a takeover. Manually dialing up a downshift did it, for instance, as did suddenly opening the driver’s door a couple of inches.
By then it was well into the early afternoon, and we headed back out with Bergmiller, who suspected that drivers getting a jump on the weekend were creating a nice highway traffic jam. Within minutes, we did indeed find a couple of waves of congestion that were just slow enough to engage the system again; and by then, accustomed to the alerts, we could experience how confident it is in its inputs and how straightforward the handoffs back to the driver are.
After a quick farewell to Bergmiller and the Audi team, we’re handed the key to a Q7—with no Traffic Jam Pilot, of course—and headed back out on the autobahn, where we soon hit some more slowdowns, a reminder of how exhausting driving in gridlock can be.
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