Je parlais avant-hier ("Prise de ris dans le véhicule autonome") de la soudaine prudence affichée par certains constructeurs, après quelques années de guerre d'annonces de part et d'autre. J'en profite pour revenir sur le sujet du niveau 3. Pour ceux qui ne sont pas familiers avec les différents niveaux d'autonomie, cette page explique l'essentiel :

  • le niveau 2 c'est ce qu'il y a dans la rue aujourd'hui, le conducteur devant rester MAITRE DU VEHICULE.
  • le niveau 3 permet de déléguer complètement la conduite dans certaines situations, par exemple dans les bouchons, mais le conducteur doit pouvoir reprendre le contrôle
  • le niveau 4 correspond au domaine de fonctionnement où le véhicule pourra "vraiment" être seul aux commandes ... qui ne couvrira pas encore toutes les situations.
  • le niveau 5 c'est le véhicule qui sait tout faire sans intervention humaine, et ça ... on sera sans doute encore en train d'en parler dans 10 ans

Mais revenons à des objectifs moins ambitieux, et à la problématique posée par le niveau 3. Il y a deux ans, plusieurs constructeurs, Ford en tête, affirmaient ne pas vouloir s'y risquer devant la difficulté à garantir que le conducteur humain reste suffisamment attentif pour reprendre le contrôle en un temps "raisonnable".
Et pour cause, même les essayeurs maison finissent par relâcher leur attention (les passages en gras sont de mon fait) :

  • Ford's Skipping the Trickiest Thing About Self-Driving Cars (wired.com, 11/2015)

There are two paths toward automotive autonomy. Conventional automakers advocate a step-by-step approach, adding features one-by-one so humans cede control over time. They argue this approach allows them to refine the technology, acclimate consumers to the coming change, and, of course, keep selling conventional cars in the meantime. Google sees that as utter nonsense and is focused solely on fully autonomous vehicles that don't even have a steering wheel. It sees no reason for the middle ground of semi-autonomy.

Ford thinks Google might be right. (...) Ford, like most automakers, sits at Level 2. Its cars have lots of active safety systems like blind spot monitoring, parking assist, pedestrian detection, and adaptive cruise control, but the driver is always in charge. With Level 3 capability, the car can steer, maintain proper speed, and make decisions like when to change lanes, but always with the expectation that the driver will take over if necessary. Ford wants to skip Level 3 because it presents the one of the biggest challenges with this technology: How to safely transfer control from the computer to the driver, particularly in an emergency. It's a balancing act, one that requires providing drivers with the benefits of autonomy—like not having to pay attention—while ensuring they are ready to grab the wheel if the car encounters something it can't handle. Audi says its tests show it takes an average of 3 to 7 seconds, and as long as 10, for a driver to snap to attention and take control, even with flashing lights and verbal warnings. (...) "Right now, there's no good answer, which is why we're kind of avoiding that space," says Ken Washington, the automaker's VP of research and advanced engineering. "We're really focused on completing the work to fully take the driver out of the loop." Fast forwarding to full automation. Ford hasn't revealed much about its capabilities, how many cars are in its test fleet, or how much ground they've covered. But Washington says a fully autonomous car within five years is reasonable, if work on the software controlling it progresses well.

As Ford Motor Co. has been developing self-driving cars, the U.S. automaker has started noticing a problem during test drives: Engineers monitoring the robot rides are dozing off.

Company researchers have tried to roust the engineers with bells, buzzers, warning lights, vibrating seats and shaking steering wheels. They’ve even put a second engineer in the vehicle to keep tabs on his human counterpart.

No matter -- the smooth ride was just too lulling and engineers struggled to maintain “situational awareness,” said Raj Nair, Ford’s product development chief.

“These are trained engineers who are there to observe what’s happening,” Nair said in an interview. “But it’s human nature that you start trusting the vehicle more and more and that you feel you don’t need to be paying attention.”

The struggle to prevent snoozing-while-cruising has yielded a radical decision: Ford will venture to take the human out of the loop by removing the steering wheel, brake and gas pedals from its driverless cars debuting in 2021. That sets Ford apart from most automakers including Audi and General Motors, which believe drivers can be counted on to take the wheel if an accident is imminent.

BMW, Mercedes-Benz and Volkswagen AG’s Audi plan to roll out semi-autonomous cars starting next year that require drivers to take over with as little as 10 seconds notice. On a scale embraced by the U.S. government, these cars would qualify as Level 3 -- more capable than cars where drivers do everything, but short of full automation.

Ford plans to skip that level altogether. The automaker has aligned with Alphabet Inc.’s Waymo, which made similar discoveries related to human inattention while researching Google’s driverless car.

“Level 3 may turn out to be a myth,” Waymo CEO John Krafcik said of autonomous cars that require human intervention. “Perhaps it’s just not worth doing.”

Dans un communiqué initialement consacré au partage des données, Volvo émet également des doutes en avril 2017 :

Mr Samuelsson expressed his concern about the so-called Level 3 autonomous driving modes. “In this mode the car is in charge of the driving, yet the driver must still be prepared to take over in case of emergency, which could be a matter of a few seconds. Volvo considers this Level 3 driving mode unsafe and will thus skip this level of autonomous driving,” Mr Samuelsson said.

Consequently, when Volvo launches its first autonomous cars in 2021, they will be at Level 4, in other words completely unsupervised on applicable roads. This means that these cars will be able to manage emergency situations and bring the car into a safe state by itself without driver interaction and that Volvo will assume liability while the car is in autonomous mode.

En février 2018 on pouvait lire le billet suivant :

As the research and development of autonomous vehicle progresses, automakers are confident about the operation and functioning of Level-4 and Level-5 automation; however, skeptical about the conditional automation i.e. Level-3. This stage of autonomous vehicle involves the handover of vehicle control to the human driver in case of emergency. The question arises that whether the driver would be in position to react promptly to the situation and take back the complete control of vehicle with in no time. It is unrealistic to expect the 100% of attentiveness of the driver in autonomous mode. Hence, the automakers are afraid of this kind of partial automation as the small distraction could lead to fatal accidents and traffic chaos. Audi has already tested its Level-3 autonomous vehicle A8 and is on verge of launching it by year end. The vehicle allows drivers to take their off eyes road and serves as traffic jam pilot. BMW and Mercedes-Benz are planning to introduce level-3 automation vehicles by next year. These L-3 vehicles need human take-over within 10 seconds. However, many automakers such as Volvo, Ford and Google are arguing about the safety of this conditional driving vehicle. These automakers are the once who have bypassed the level-3 automation and jumped directly to fully autonomous level-4 and level-5 featured vehicles. Toyota also have similar take on this. The company finds L-3 automation difficult to accomplish as compared to fully autonomous L-4 and L-5. Ford and Volvo considers level-3 as myth and the most unsafe automation. Hence, these OEMs are skipping L-3 to offer L-4 vehicles earliest by 2021. Many researchers believe that skipping L-3 and directly introducing L-4 and L-5 will create market opportunities for fully autonomous vehicles and ride sharing

Mais bizarrement, début 2019, changement de programme chez Ford !

Now, Ford is embracing the stepping-stone approach, with the aid of cameras and other systems that can ensure drivers are paying attention at the wheel.

"Taking steps to get there as opposed to a big bang is more practical," Marcy Klevorn, Ford's president of mobility, told Automotive News on the sidelines of the Detroit auto show last week. "I think it allows us to provide autonomy in step functions to get people used to it. Acceptance is going to be a big deal; this is totally a different way to move." Ford still plans to deploy Level 4 commercial vehicles at scale in 2021. In the meantime, it's offering more advanced semi-autonomous systems that can take control of the wheel and pedals for very short periods of time.

L'objectif du L4 en 2021 est officiellement maintenu, mais je pense que si le niveau 3 s'impose de nouveau c'est simplement parce que Ford, comme tous les autres constructeurs, ne voit pas comment faire du niveau 4 à "court terme" (disons <2025)
On appréciera au passage le "for very short periods of time" :)