Honda's Level 3 system for automated driving has limits

TOKYO — When Honda Motor Co. started leasing the world's first Level 3 autonomous vehicle in Japan last year, the move heralded a new era of self-driving convenience for car owners.

But a recent test drive of Honda's car on the expressways of Tokyo shows just how far away real self-driving remains. In some ways, the system even introduces a whole new level of stress.

Honda took an early lead on the global industry last March when it launched the Legend Hybrid EX in Japan equipped with the top-shelf Honda Sensing Elite suite of driver-assist technologies.

The sedan's Traffic Jam Pilot was the first Level 3 automated-driving system approved by Japan, and the first available in a production vehicle for public road driving anywhere in the world.

The promise is hands-off, eyes-off driving on 90 percent of Japan's highways — even allowing the driver to sit back and watch TV on the center console as the car seamlessly negotiates traffic.

But the reality shows the limits of Level 3 driving, an increasingly controversial steppingstone on the path to fully self-driving vehicles.

Level 3 lets the car drive itself under most circumstances, but requires the driver to take the wheel in a pinch. The safety concern is that some human drivers, lulled into complacency by the computer chauffeur, will zone out and fumble the handoff.

Some automakers are now steering clear of Level 3, or planning to leapfrog it altogether.

Honda's system, available only in Japan, is a technological wonder deployed in the brand's Legend sedan. The Legend was sold in the U.S. as the Acura RLX before American Honda Motor Co. dropped it.

Honda produced a limited run of only 100 vehicles with Level 3 at its Sayama assembly plant, which ended vehicle production on Dec. 27 as part of Honda's global restructuring. The special-edition Legend went on sale March 5, and costs ¥11 million ($96,000), a ¥3 million ($26,000) premium over the car's regular version.

By last October, Honda had sold only about 80 of them.

Honda's Level 3 system uses five lidar sensors from Valeo, five radar units from Continental, two cameras and a global navigation satellite system to steer itself down the road.

But the system operates only in a narrow band because it is geared for use in traffic jams. It can be activated only when the car is going faster than 18 mph. After that, Level 3 can operate in a range from 0 to 31 mph.

But in an hour-and-a-half test drive on Tokyo's expressways, even during rush hour, conditions were never quite right to luxuriate in Level 3's self-driving mode. For a fleeting moment, on a stretch leading to Tokyo's Haneda international airport, Level 3 actually did kick in. But almost as quickly, the car exceeded 31 mph — and control was thrown back to the driver.

To be sure, the technology is envisioned as working only in low-speed stop-and-go traffic. And there are certain stretches of city expressways, with tight curves, where it won't work at all.

Such limitations are partially an acknowledgment that Level 3 still isn't ready for the wide gamut of real-life driving scenarios. Its practicality is also curbed by the upper speed limit — in actual traffic-jam driving, the flow is often punctuated by spurts of speed greater than 31 mph.

Honda's Level 3 system aims to reduce fatigue, and it achieves that to some extent. But the upshot is that the human driver must still be on alert to take control at a moment's notice. Despite saying drivers can relax and watch videos, Honda also warns them not to eat, recline or wear sunglasses. Such behavior might interfere with the car's ability to monitor the driver.

Indeed, the system gives drivers just 10 seconds to take control. If the driver is unresponsive, the car escalates its warnings through a series of orange lights, buzzers and tugs at the seat belt, until the car finally pulls itself over on the shoulder and calls emergency.

Germany's Continental AG supplies the Legend's four corner radar and one long-range radar as well as one of the electronic control unit that melds sensor data into an "environment map" of the car's surroundings. Continental delivers its highest-level automated driving technology to Honda partly because German brands don't offer Level 3 yet, Continental Japan CEO Bert Wolfram said.

Audi, for example, also has vehicles equipped for Level 3 Traffic Jam Pilot technology, but the German luxury brand still hasn't turned on that capability. And Honda hasn't deployed Level 3 in the U.S. market because it says the infrastructure there is incompatible with its system.

Stellantis said in December that it will roll out hands-free Level 3 automated driving technology within its cars starting in 2024. The technology to allow the driver to hand over control to the vehicle is being developed in partnership with BMW, the automaker said. BMW could debut Level 3 technology as early as this year in the next-generation 7 Series premium sedan.

Continental believes in the step-by-step march toward full autonomy, Wolfram said, and the company is happy to provide such systems to automakers, even for Level 3 systems.

Partnering with Honda on the world's first Level 3 system is a pride point, Wolfram said, noting that the environmental modeling required by Honda's system is "very complex."

Continental's collaboration with Honda is part of the supplier's move to provide "full stack" products that integrate hardware and software for plug-and-play procurement by manufacturers.

Naoto Okamura contributed to this report.