Yahoo Autos Semi-Autonomous Comparo! Tesla, BMW, Mercedes-Benz, and Infiniti
From the February 2016 issue
Autonomous driving—what the high-minded call artificial intelligence and what we call real brainlessness—may not be as vile as we originally feared. One DeLorean DMC-12 directed by a Stanford University engineering crew can perform perfect opposite-lock, tire-cooking, hands-off donuts at will for as long as the rubber lasts. Lead professor Chris Gerdes explained the rationale underlying this class project, timed to coincide with the fictional arrival on October 21, 2015, of the time-traveling Back to the Future DeLorean: “When we no longer have a human driver in the loop, we think that the automated vehicle should be able to harness the full range of vehicle operating capabilities to avoid collisions, even if this means going sideways a bit to stay on the road.” In other words, loading $60,000 worth of navigation gear, two powerful electric motors, and shrewd software into a 30-year-old sports car may have just fried Google’s autonomous eggs.
While on-demand drifting will likely remain in your dreams for the time being, cars programmed to perform other feats are now commonplace. Anti-lock brakes and stability control have been mandatory for years. Lots of cars sound an alarm, shake the seat, and/or nudge the steering wheel when you leave your lane without signaling. Adaptive cruise control that automatically maintains a safe distance from the car ahead is also widely available. Ten manufacturers recently committed to making automatic emergency braking standard across their entire lineups.
Brainless driving is closing in on us like a meteorite because of its potential to avoid accidents. Sadly, we are a nation of mediocre drivers, distracted on our daily journeys by dining, child rearing, makeup applying, and incessant texting. Driver’s ed. is a shadow of its former self, and few of us are able to use the accident-avoidance capabilities built into every new car. Our driving errors cause crashes, injuries, and fatalities.
So while we’re getting worse behind the wheel, the sensors and algorithms capable of saving us from ourselves are getting better. And though we’re not convinced that this will ever yield totally hands-off personal transportation, scores of manufacturers are working feverishly to prove us wrong.
To gauge progress on the path to brainlessness, we’ve gathered the four luxury cars that have done the most to purge human frailties from the acts of cruising, braking, and steering.
As usual, our test regimen is a balanced mix of on-road evaluations and proving- grounds tests. Other than noting which car can and which can’t steer you snugly against a curb, we skipped automatic-parking maneuvers. All these cars and many others on the market keep watchful eyes on your blind spots, a second form of artificial intelligence we’re taking for granted here. To verify that adaptive cruise control works to maintain a safe interval between your car and the one immediately ahead when an intruder barges into your lane, we used a foam-filled Volkswagen Golf decoy owned by Bosch to supplement our over-the-road observations. Our main focus was automatic lane keeping: how well these four early semi-autonomous cars guide you safely and securely while relying on their electronic wits instead of the driver’s hands, eyes, and judgment. Using a 50-mile mix of freeway stretches, rural two-lanes, and city streets, we tabulated exactly how many guidance interruptions were caused by broken lane marks, inconsistent pavement patches, intersections, and exit and entrance ramps. We also noted when a car lost the lane-keeping sense for no apparent reason. Then we ranked the four contenders according to the number of control lapses each test car experienced.
So cinch up nice and tight, because there’s going to be a lot of near misses.
See scoring and results and a breakdown of each car's technology
As the first car on the road with steer-by-wire capability (don’t fret, there are mechanical backups), Infiniti’s mid-size four-door is armed and ready to relieve your brain of some driving tedium. It’s not only smart enough to apply the brakes when the car ahead in your lane slows, it’s supposedly capable of leap-frogging that car to detect when a driver two spots ahead impedes traffic flow.
We didn’t verify that capability, but we did use both normal traffic and Bosch’s lane-intrusion tool to confirm that the Q50 will forcefully apply the brakes to avoid a rear-ender when the space between you and a car ahead is suddenly diminished. Our only gripe is that the maximum car-to-car interval provided by this adaptive cruise control is a bit short for our tastes. While the owner’s manual lists a 200-foot margin at 60 mph, the gap we observed felt substantially shorter. (The three other cars in this examination also passed the adaptive-cruise-control interruption test with flying colors.)
Activating the Q50’s Active Lane Control and Lane Departure features, part of a $3200 Technology package, and Direct Adaptive Steering from the $3100 Deluxe Touring package requires a visit to the vehicle-systems settings menu and a tap of a switch on the right steering-wheel spoke. These driving aids work with or without cruise control engaged by monitoring the edges of your lane of travel with one forward-looking camera. On our route, with lane markings that ranged from abysmal to perfectly clear, the Q50’s hands-free lane-keeping ability was a mixed bag. On straight sections it worked nicely even in the rain, which gives some car cameras fits. But in mild curves, and when lane markers were interrupted by entrance and exit ramps or intersections, it lost the scent. The Q50 would wobble the full width of the lane before sounding three gentle beeps to signal the need for helping hands on the wheel. Our sincere apologies to those drivers behind us on I-94.
One of the Q50’s distinctive traits is that its steering wheel remains dead still when this car’s path is under Direct Adaptive Steering control. That’s interesting, but what matters more here is how well this Infiniti locks onto and holds a lane hands-free, which, as we found out, is not that well. Logging 93 interruptions on the 50-mile route, the Q50 finished dead last in this group by a wide margin.
Mercedes dipped a toe into the semi-autonomous pool three years ago with the introduction of the sixth-generation S-class. Proceeding cautiously in waters infested with liability sharks, Mercedes offers its Distronic Plus with Steering and Active Lane-Keeping Assist as standard equipment on some S-class models and optional on others. (It’s standard on the S65 and part of a $2800 Driver Assistance package in the base S550 sedan.)
Pressing two buttons located to the left of the instrument cluster enables this system of bundled functions. When you’re ready for lazy driving, a tug of the cruise-control stalk activates adaptive cruise control, lane keeping, and hands-off steering. Once the S-class’s nervous system locks onto lane markings, a small gray steering-wheel symbol in the cluster glows green.
At cruising speed, this hands-off function lasts 12 seconds, then the green wheel turns bright red, presenting three options: Do nothing and you’re scolded after a three-second delay by a reminder tone, though the lane-keeping function does continue; you can give the wheel a quick left-right tug to reset the 12-second clock; or simply take over and steer the good old-fashioned way.
We experienced scores of dropouts on our 50-mile route (not counting the times we reset the hands-off-driving clock). These interruptions were triggered by lane markers obliterated by pavement patches, intersections, and edge-mark lapses at freeway entrance and exit ramps. But overall, Distronic Plus, which sees the road with one stereo camera and five radar sensors, works surprisingly well. There was minimal loss of functionality during night driving and in rainy conditions.
During one lengthy stretch of stop-and-go freeway traffic, steering and lane-keeping assistance both remained active indefinitely with the red-wheel icon (remember it usually lights every 12 seconds if your hands aren’t grasping the wheel) mercifully on hiatus. To our chagrin as dedicated drivers, automatic control over speed and direction while the car crept forward was quite relaxing. So give the Benz an honorable mention for its exemplary traffic-jam behavior (especially if you commute anywhere near Los Angeles) and a third-overall rank resulting from the 58 dropouts the S65 accrued on our test route.
To make its stand in the luxo-tech wars, BMW introduced the ominously named Active Driving Assistant Plus as $3600 optional equipment on its new 2016 7-series flagship. The functions mirror that of the Mercedes with a couple of exceptions. Here, the controls are mounted in plain sight on the left steering-wheel spoke, instead of hidden behind the wheel on a stalk. Another notable difference is that BMW gives you only three seconds of totally hands-off steering assistance before a green steering-wheel icon turns yellow (with assistance still in force for seven more seconds), then red (assistance suspended).
Simply touching the steering wheel reboots guidance. Experimenting, we learned that light pressure from two fingers—without any actual steering—was the minimum required to convince the capacitive rim sensor that a brain was present to supervise the 750i’s progress.
In addition to the green, yellow, and red symbols, Active Driving provides steering-wheel vibrations that can be adjusted to three intensities. It’s capable of tracking via lane markers (indicated by green-lit lines to the sides of the steering wheel) or by following a car ahead (marker lines not illuminated).
BMW’s hands-off steering works at night and in the rain. As is the case with the Infiniti and Mercedes systems, there are lapses in sweeping bends or when exit and entrance ramps interrupt one lane stripe, for example. City streets also foil this equipment; occasionally the BMW lost the trail on clearly marked straight sections of pavement for no obvious reason at all.
The 56 interruptions we tallied on our drive route and a lower overall need for minding the wheel gave the BMW 7-series a huge jump on the Infiniti Q50S and a thin edge over the Mercedes S-class.
The sedan that begs to differ is this test’s clear winner. With utmost confidence and only two cautions from legal counsel—“Always keep your hands on the wheel. Be prepared to take over at any time”—the Tesla Model S locks onto the path ahead with a cruise missile’s determination and your hands resting on your lap. Tesla’s Tech Package with Autopilot costs $4250 and uses one camera and one radar sensor.
A thin control stalk tucked behind the left steering-wheel spoke commands the cruise-control speed (up or down clicks), the interval to the car ahead (twist of an end switch), and Autosteer initiation (two quick pulls back). A chime signals activation, and the cluster displays various pieces of information: the car ahead, if it’s within radar range, and lane marks, illuminated when in use for guidance. A steering-wheel symbol glows blue when your steering input is no longer needed, and Tesla’s gauge cluster also displays the speed limit and your cruise-control setting.
The Model S knows its way via two tracking mechanisms: locking onto the car ahead or sighting the lane marks. When there’s difficulty reading the road, a “Hold Steering Wheel” advisory appears. If lane keeping is interrupted, a black wheel gripped by red hands and a “Take Over Immediately” message appear on the dash. Failing to heed these suggestions cues chimes, and if you ignore all the audible and visible warnings, the Model S grinds to a halt and flashes its hazards. A heartbeat detector is not included.
The Tesla’s Autosteer performance can be distinguished from our other contenders by two words: no wobbling. This car identifies the exact center of your lane of travel and holds that course with minimal deviation. This system rises well above parlor-trick status to beg your use in daily driving.
Also to Tesla’s credit, this is the only car capable of hands-free lane changes. You simply use the turn signal the normal way and the Model S glides smoothly into the next lane after verifying that there’s space to do so safely. To move two lanes, you must signal that desire with two separate flicks of the stalk. This function also can be used on freeway entrance and exit ramps. Of course, you must check the cruise control’s set speed to make sure you don’t exceed the car’s cornering grip on a tight ramp.
A rainy night laced with heavy spray from adjacent traffic did dent lane keeping’s confidence, let’s say by 15 percent, but by tallying only 29 interruptions in 50 miles, Tesla’s Autopilot app lives in a class of one.
This comparison test reminded us how much pleasure we reap from the simple act of controlling our speed and place in the grand traffic stream. And it has convinced us that the best feature of any autonomous-driving technology is an off switch.
Our view is hardly universal. In fact, a dissenting outlook exists where you’d least expect it. Toyota president Akio Toyoda recently speculated that: “In the other world, the fun-to-drive world, autonomous driving technology will let drivers who are really interested in driving attain driving skills beyond their actual capabilities. There is a gap between the driver’s natural ability and what they want to obtain. Autonomous driving will fill that gap.”
But Akio, if computers handle all the thinking and acting, how will a driver’s natural ability ever improve?
2016 BMW 750i xDrive
A stereo camera located near the rearview mirror gives the BMW depth perception to identify pedestrians and lane markings. Five radar units, including one in the lower grille, monitor traffic from every direction.
2015 Infiniti Q50S
One windshield camera provides vision for lane control while others operate the rain-sensing wipers and automatic high-beam control. Radar at the left side of the grille enables adaptive cruise control.
2015 Mercedes-Benz S65 AMG
Like BMW, Mercedes uses a stereo camera system mounted behind the windshield to see lane markings, plus an array of five radar units looking forward and to the sides to spot both nearby and distant traffic.
2015 Tesla Model S P85D
One windshield camera and a radar sensor mounted low in the grille give the Model S what seems like 20-20 vision. Ultrasonic sensors (not shown) check for a clear path to the side before enabling a lane change.
Test Results
BMWINFINITIMERCEDESTESLACRUISE-CONTROL-SETTING RANGE, MPH19-10619-10920-11818-89CRUISE-CONTROL RESPONSE TO LANE INTRUDEREXCELLENTEXCELLENTEXCELLENTEXCELLENTNUMBER OF LANE-CONTROL INTERRUPTIONS ON 50-MILE ROUTE56935829LANE CONTROL AT NIGHT, IN RAINGOODGOODGOODGOODWHEEL FORCE TO REGAIN STEERING, LB2434LANE-CHANGE ABILITYNONONOYESPARKING ASSISTANCEYESNOYESYES
Progress, of a Sort: Autonomous Milestones
• Over the course of six years and more than a million miles of autonomous driving, Google prototypes have suffered only a dozen or so fender benders. Google claims that its vehicles, governed at 25 mph, weren't at fault.
• A Mountain View, California, motorcycle cop pulled over a Google car driving 24 mph in a 35-mph zone for impeding traffic. Regrettably, no ticket was issued.
• Toyota recently recruited DARPA robotics head Gill Pratt, arming him with a five-year, $1 billion budget to pursue artificial intelligence and robotics technology. With fingers crossed, Toyota president Akio Toyoda wished, "One hundred years from now, I would like vehicles to remain loved by people."
• German media speculates that Apple may team with BMW on Apple's i3-based Project Titan.
• Last year, Audi's "piloted driving" A7 traveled 560 miles from Silicon Valley, California, to Las Vegas, Nevada, with minimal driver input, experiencing both open-road and city-traffic situations.
• Porsche's InnoDrive uses onboard-navigation data to improve cruise-control speed and fuel efficiency during twisty-road driving. Audi may be the first to introduce this system in European models.
• At last fall's Tokyo auto show, Nissan presented its latest Intelligent Driving System concept, combining artificial intelligence and electric propulsion, describing the car as "relaxing in a living room."
• Renault-Nissan claims 10,000 employees at work on autonomous-driving commercialization.
• MIT's Persuasive Electric Vehicles combine Uber, electric propulsion, and autonomous driving in experimental three-wheelers programmed to carry one passenger or cargo in cities.
• Following Tesla's push of its Autopilot software last October, YouTube was rife with back-seat "driving" and other stunts. Tesla boss Elon Musk announced "additional constraints" to follow, though no details were included.
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