Honda, Toyota Intro More-Advanced Driver-Assistance Systems

Honda Sensing Elite and Toyota’s Advanced Drive launch in Japan but are likely to proliferate to other regions, including the U.S.

The Japan-market Honda Legend employs front and rear lidar to complement radar and camera sensing. (Honda)

Honda and Toyota each recently announced the release of new, more-sophisticated driver-assistance systems for a special range of vehicles available in Japan starting in March of this year. Honda attracted global attention in November 2020, when it announced the Honda Legend fitted with Honda Sensing Elite would be the first vehicle ever awarded “type designation” from Japan’s Ministry of Land, Infrastructure, Transport and Tourism (MLIT) for a driver-assistance system of SAE Level 3 capability.

When a “takeover” by the driver is required, all Honda Sensing Elite cockpit indicators flash orange. (Honda)

The Legend is joined by Toyota’s 2022 Mirai and Lexus LS500h equipped with Advanced Drive, a system that, the company said in a release, embodies its “Mobility Teammate Concept – an automated driving concept unique to Toyota that seeks to enhance communication between drivers and cars, enable them to reach out to each other for mutual assist.” Toyota made no direct statement about Advanced Drive’s position in the SAE Levels of Automation hierarchy and the system does not offer the feature that Honda said elevates its Sensing Elite to Level 3 capability.

Steering-wheel indicators light blue to signal hands-off driving is permissible. (Honda)
Honda Sensing Elite adds an instrument-cluster prompt to cockpit light indicators to signal a driver takeover is required. (Honda)
Instrument panel prompt in the Lexus LS 500h has a blue tone to indicate conditions are proper for hands-free driving. (Toyota)
Advanced Drive instrument cluster indication for potential automated overtaking maneuver. (Toyota)
Example of a complex freeway-exit maneuver handled by Advanced Drive. (Toyota)
Advanced Drive front lidar sensor just below license plate of Lexus LS 500h. (Toyota)

The new systems continue to blur the descriptions of – and differences between – SAE Level 2 and Level 3 driver-assistance, but their close introduction in production models also helps to clearly demarcate the chief differentiator between Level 2 and Level 3 capabilities.

Honda’s Level-3 functionality

Honda’s press information about Honda Sensing Elite indicates that its function called Traffic Jam Pilot enables Level 3 capability in that the driver is not driving when the feature is active – and the driver does not have to monitor the system in the event a “takeover” is required. But as per Level 3 description, if the feature does request driver takeover, the driver must be prepared.

Honda’s formal description of Traffic Jam Pilot: “While driving using the Adaptive in Lane Driving, if the vehicle gets caught in traffic congestion, under certain slow-speed conditions, the system can take control of acceleration, braking and steering while monitoring the vehicle’s surroundings on behalf of the driver. The system “drives, stops, and resumes driving within the same lane while maintaining a proper following interval in accordance with the speed of the vehicle detected ahead. While the vehicle is under the control of the system, the driver can watch television/DVD on the navigation screen or operate the navigation system to search for a destination address, which helps mitigate driver fatigue and stress while driving in a traffic jam.”

Stipulating that the driver’s attention can be elsewhere while operating in Traffic Jam Assist mode is the aspect that largely separates Level 3 operation from Level 2. According to the SAE J3016 Standard for the Levels of Driving Automation, the driver must constantly supervise in all situations when using a Level 2 driver-assist system.

Meanwhile, Level 3 provides for fully automated operation, but only under limited conditions – in the case of Honda Sensing Elite, the comparatively narrow situation of low-speed, heavy freeway traffic when no lane-changing is necessary or desired. The company claims the system’s development encompassed some 800,000 miles (1.3 million km) of expressway driving and “approximately 10 million patterns of possible real-world situations were simulated.”

Multiple sensors, 360-degree awareness

Critically, the Legend equipped with Honda Sensing Elite is fitted with a robust array of sensors that includes five lidar emitters – two on the front and three at the rear. Although the cost of lidar has been radically cut in recent years, the technology remains expensive for series-production models – perhaps one reason why Honda is offering only leasing for the vehicle. The information from lidar is fused with that from five radar sensors and two front-facing cameras to provide a 360-degree view of the Legend’s surroundings. Honda said the system also relies on 3D high-definition maps and global navigation for dead-reckoning of the vehicle’s position and other information about road condition.

Similar to Cadillac’s Super Cruise and other automakers’ Level 2 driver-assist technology, Honda Sensing Elite also enables hands-off driving in an expressway or Interstate-highway type of environment, the company claims. The system’s adaptive cruise control, low-speed follow and lane-keeping assist functions must be activated, then the system will allow hands-free driving within a single lane (Adaptive in-Lane Driving). While in this mode, if the driver activates the turn signal to indicate a desired lane change, “the system provides throttle, braking and steering inputs necessary to accomplish the lane change,” Honda said.

But the system will go further in hands-off operability by executing a lane change without driver input. When the Active Lane Change with Hands-off Function is enabled by the driver, Honda Sensing Elite “assesses the situation and assists the lane change and/or passing of the other vehicles under certain conditions,” Honda explains. When the system detects a car in front being driven at low speed, it “notifies the driver and then assists with the passing of the vehicle and the return to the original lane.”

In the cabin, the Legend employs a unique lighting system as the signature feature of a human-machine interface designed to allow the driver “to instantaneously recognize the operating status of the system, the driving situation and any handover requests issued by the system.” Indicator lights on the steering wheel, at the top of central touchscreen and the top of the glovebox area illuminate to indicate various system activation levels.

The steering-wheel light alone indicates hands-off functions are activated, while blue lights at all three points indicate activation of Traffic Jam Pilot. All three lights blink orange to indicate the system requesting a “handover” for the driver to take control. On the Legend’s exterior, Honda engineers and stylists have incorporated the lidar and radar emitters in the front and rear fascia areas in a fashion that makes them barely visible, while subtle blue running lights in the front fascia indicate to outsiders that the car is operating in a driver-assist mode.

Toyota’s driving ‘Teammate’

The 2022 Lexus LS 500h and Toyota Mirai that offer Toyota’s new Advanced Drive driver-assist. (Toyota)

In saying its new Advanced Drive driver-assist system is a based on the Mobility Teammate Concept, Toyota seems to be splitting the difference between its two long-discussed driving-automation strategies: “Guardian” for safety-focused driver-assist functionality that operates largely in the background and “Chauffer” for more-sophisticated degrees of automated control. Of Advanced Drive. In announcing the system’s availability in Japan, the company stated, “With the aim of ensuring that drivers remain the focus even as technologies advance, the driver and car confirm each other's status by engaging in a dialogue, leading to safe driving and comfortable mobility.”

The Advanced Drive system is designed exclusively for expressways or other vehicle-only roads, Toyota said. After inputting a destination into the vehicle’s navigation system, Advanced Drive will “detect the situation, make decisions, and assist driving under the driver's supervision according to actual traffic conditions. It can keep the vehicle in its lane, maintain the distance from other vehicles, navigate a lane split, change lanes and overtake other vehicles until leaving the roadway for the destination.”

Like Honda’s new system, the driver can entrust a lane-change to automation by using the turn-signal lever; Advanced Drive also will automatically adjust speed to accommodate a vehicle merging into the highway. The 2022 Lexus LS 500h and Mirai fitted with Advanced Drive use a single, low-mounted front lidar sensor. The cars also incorporate Advanced Park, which uses 360-degree sensing to fully control throttle, steering and brakes for parallel and back-in perpendicular parking maneuvers.

Over-the-air (OTA) updates – for both control and mapping software – will keep the Advanced Drive system contemporary with new functions and enhancements. But in a strategy that has the potential to raise privacy concerns, Toyota said that in the Japan market, certain driving data will be collected. It also said that “the privacy and security of the drivers and individuals captured on camera are taken into consideration when this data is collected and processed.”