Walking into your local showroom and buying a fully autonomous vehicle remains a distant prospect in 2022. Yes, automakers continue to build cars with detachable steering wheels and the like, but the red tape to getting many of these vehicles approved and on the road remains formidable. Currently, most vehicles go no further than Level 2 autonomy, and while a few like the Mercedes-Benz S-Class have launched with Level 3 capabilities, it seems that not many will follow. Instead, a more likely scenario is that cars will leap from Level 2 to Level 4, according to several executives in the industry. This is because Level 3 poses a unique set of challenges that are enormously difficult to overcome, but what are they?

As per Automotive News, a panel of experts recently sat down at the Center for Automotive Research's Management Briefing Seminars to discuss the progress of advanced driver-assist systems. We already know that the gap between a Level 2 system such as Ford's BlueCruise and a Level 4 system is huge, with the latter enabling the car to be driven by itself under most conditions. Despite this gap, panelists feel that Level 3 systems - defined by the SAE as requiring the driver to take over in certain conditions - is less feasible. And yet, both Genesis and BMW are set to roll out Level 3 systems imminently.

"Handing the controls back to the driver is very challenging," said Greg Brannon, director of automotive engineering and industry relations at AAA. He used the example of getting a driver to transition from a phone call to full engagement with traffic. Reengagement can take a good few seconds in cases like this and, especially at higher speeds, this could pose a danger if the driver doesn't react in time.

The panelists specifically pointed to emergency situations where the lack of time can make it difficult for a driver to regain attentiveness and act quickly enough.

For a Level 4 system to work correctly, it must be able to replicate a human's perceptions and the many small, constant adjustments that are made. If it can do this, it can be considered a safe option.

Our takeaway is that a car is at its safest when either the driver (Level 2 and below) or the autonomous systems (Level 4 and above) assume the majority of the control. Problems arise at Level 3 when there is less clarity over whether the human or car takes the lead.