Toward a Self-Driving Future: Japan Green-Lights Level 4 Autonomous Vehicles

Current State of Autonomous Driving

The town of Eiheiji in Fukui Prefecture created considerable buzz in the domestic and global media when it launched Japan’s first driverless transportation service in May of this year. To an average observer, it appeared as if the long-imagined future of roads filled with self-driving cars was just around the bend. Looking at the current state of the industry, however, provides a more sober picture. Even with recent technological advances, a variety of factors make the outlook of autonomous vehicles becoming widely commercially available any time soon a distant prospect at best.

Eiheiji launched its passenger service following the government amending Japan’s Road Traffic Act in March of this year to allow fully driverless vehicles to operate under certain conditions, so-called level 4 autonomous driving. In simple terms, the new government regulations enable vehicles guided by a computerized driving system taking the place of human drivers to run on public roads, but only under strictly regulated parameters dictating things like times and zones of operation and the maximum speed of vehicles.

The vehicles used for Eiheiji’s service are roofed carts developed by a consortium consisting of Yamaha Motor, the National Institute of Advanced Industrial Science and Technology, Mitsubishi Electric, and Soliton Systems. Seating up to seven passengers, the carts are equipped with cameras and other sensory equipment that collect data that enable vehicles to navigate according to road conditions.

Prime Minister Kishida Fumio, center, steps out of a self-driving cart after going for a test ride on Eiheiji’s transportation service on February 4, 2023. (© Jiji)

With the launch of the service, Japan joins the United States and other countries in offering transportation self-driving services featuring Level 4 vehicles. In the United States, Cruise, a subsidiary of US automaker General Motors, launched its fleet of robotaxis in Austin, Phoenix, and San Francisco in 2022. Using a version of the commercially available all-electric Chevrolet Bolt, the service feels more akin to ridesharing than the carts in Eiheiji. However, just as in Japan, the cars are subject to strict regulations as Level 4 autonomous vehicles, including being limited to top speeds of 48 kilometers an hour and non-rush-hour operation when pedestrian and car traffic is light.

A Cruise robotaxi on the streets of San Francisco. (© Cruise)

Waymo, a subsidiary of Google’s parent company Alphabet, is another US autonomous ride-hailing service. Available in Los Angeles, Phoenix, and San Francisco, it operates 24 hours a day. But like Cruise, Waymo’s fleet of vehicles is subject to strict regulations, including being limited to narrow, designated zones within cities.

Waymo’s self-driving Jaguar I-Pace. (© Waymo)

Companies tapping into the commercial potential of Level 4 autonomous driving have so far focused on robotaxis, touting driverless technology as a means of cutting labor costs and dealing with driver shortages in different transportation fields. However, considerable hurdles remain before fully autonomous driving technology will become widely available on cars for private use.

Toward a Driverless Future

The Society of Automotive Engineers created its Levels of Driving Automation, which has served as the industry’s leading guideline in assessing self-driving features. It consists of the following six ranks.

- Level 0: Driver support systems like collision warnings and emergency braking, but no driving automation technology.

- Level 1: Driver assistance for steering, braking, or accelerating.

- Level 2: Partial driving automation for steering, braking, or accelerating.

- Level 3: Automated driving features limited to certain conditions with a human driver present.

- Level 4: High driving automation limited to certain conditions without a human driver.

- Level 5: Full driving automation in all conditions.

In simple terms, the first three levels describe vehicles equipped with differing degrees of driver-support features, and the latter three denote cars capable of automated driving. Fully driverless vehicles like robotaxis and shuttles fall under Levels 4 and 5.

Current automated driving technology has reached as far as Level 4 in some markets. Except for a very few specific cases, though, commercially available systems remain at Level 2. The first automaker to officially offer Level 3 features in Japan was Honda in 2021, with its advanced driver assistance system Sensing Elite, which allows for handless driving in congested highway conditions. While Honda has touted the system as being capable of taking over in traffic jams, freeing drivers to watch television or movies on the car’s monitor, it has a number of restrictions, including being limited to low-speed situations of 50 kilometers an hour or less and only engaging if the vehicle is traveling below 30 km/h. Honda featured the system on a limited run of 100 units of its luxury Legend model, which it priced at an eye-watering ¥11 million, some ¥4 million more than the standard model, and only made these available for lease.

Sales of Legend models featuring the company’s Sensing Elite system ended in January 2022. (© Honda)

Another advanced conditionally automated driving system is the Drive Pilot by Mercedes-Benz. The German car maker has since May 2022 offered the systems on its EQS and S-Class models for an additional €7,000 and €5,000, respectively. However, use is limited to Germany’s autobahn motorway network, and includes other deployment restrictions, such as being constrained to speeds of less than 60 km/h.

The Mercedes-Benz EQS uses an automated driving platform designed specifically for electric vehicles. (© Mercedes-Benz)

Mercedes-Benz in earning authorization from the German government has proclaimed its auto-drive technology as the first in the world to be “internationally approved” for Level 3 driving under the stringent United Nations R157 framework regulating automated lane-keeping systems. Honda’s Sensing Elite system is on a par with Drive Pilot in terms of functionality, but the car maker’s approval from Japan’s Ministry of Land, Infrastructure, Transport, and Tourism did not include UN-R157 credentials.

Even in meeting UN regulations, Level 3 systems must still receive country and regional authorization, a slow process that has so far limited Drive Pilot’s rollout to Germany. Progress is being made, though. To date, Nevada in the United States has also approved the technology, and California is in the process of approving it.

Hurdles for Consumer Automobiles

By comparison, Level 2 technology like adaptive cruise control and active braking have become common features on consumer vehicles around the globe. In terms of the ability to keep cars within their lane, there is no real difference between Level 2 and Level 3 systems, and in fact the former allows for a much wider range of speeds and road conditions while being significantly less expensive. What, then, makes Level 3 systems more advanced?

The primary difference is that with Level 3, the task of driving the vehicle shifts to the car itself, enabling human drivers to take their eyes off the road. This is a significant jump from Level 2 and demands that systems meet higher standards of reliability and safety for authorization. Needless to say, such technology is costly to develop, which is reflected in the high price of systems. In addition, autonomous driving raises issues of liability, such as who is to blame in the event of an accident, considerations that governments and experts are currently working out.

Toyota’s mobility vehicle e-Palette, which transported passengers within the Athletes’ Village at Tokyo 2020 Olympic and Paralympic Games, paused operations after a shuttle collided with a visually impaired pedestrian. An investigation of the incident found human error to be the cause. (© Toyota)

A common criticism of Level 3 systems is that for their price, they offer little extra advantages beyond enabling drivers to take their eyes off the road for short stretches. Even this feature is in doubt, though. I took a Honda Legend equipped with Sensing Elite for a test drive and found it to be more constrictive than freeing, as the system sounded an alarm warning me to keep my eyes on the road if I glanced anywhere other than straight ahead or at the car’s central display.

This highlights that even with all their hype, Level 3 systems still require that drivers remain ready to take control of the vehicle at a moment’s notice. Subsequently, it is easy to imagine that consumers will find Level 2 technology more than adequate in terms of cost and function, which is why systems like Drive Pilot and Sensing Elite have not been made more widely available.

Consumers can expect the cost of Level 4 systems to be even higher when they become commercially available as they call for more precise and reliable map data than those for more commonly available navigation systems. Indeed, to date autonomous driving systems of Level 3 and higher have been limited to specific areas due to the high hurdle of authorization by national and regional authorities and the difficulty of sourcing the high-precision map data they require.

The need for transportation companies to decrease labor costs and address driver shortages will boost demand for Level 4 and Level 5 self-driving systems like robotaxis and shuttle services. However, the costs of this technology will have to come down significantly before regular car buyers can begin to dream of owning an autonomous vehicle, a prospect that I estimate is at least a decade away.

(Originally published in Japanese. Banner photo: The Zen Drive Pilot Level 4 transportation service kicks off in the town of Eiheiji, Fukui Prefecture, in May 2023. The autonomous shuttles seat seven passengers and traverse a 2-kilometer route along a public road, reaching the speed of 12 km/h. © Jiji.)