Autonomous driving levels and enablers Chapter | 17 191• Level 4, full self-driving automation: All safety-critical functions are
handled by the vehicle at all times, as well as the roadway monitoring. This
design assumes that the driver is not always available to take control and can
apply to occupied and unoccupied vehicles.
The most recent study of the Society of Automotive Engineers (SAE
On-Road Automated Vehicle Standards Committee, 2018) provides the J3016TM
“Levels of Driving Automation” standard, which defines six different levels of
autonomy that cover a wide range of driving autonomy.
• Level 0, no automation: The responsibility for the vehicle’s movements is on
the driver. Even when warning and alert systems exist, the driver is respon-
sible for how to interpret these elements.
• Level 1, basic driving induction systems: The vehicle offers basic assistance
services (e.g., cruise control and parking assistance), but the driver plays a
predominant role in driving and driving.
• Level 2, partial autonomy: The vehicles of this level can only be driven
under certain conditions and require continuous inspection by the driver.
This is the most common level of autonomous vehicles in the market such as
Mercedes-Benz and Tesla. At this level, the driver and not the manufacturer
is responsible for the vehicle’s safety. This makes it easier for companies to
take the technology on the road but requires drivers to “remember” that they
must be ready to take the lead in order to avoid accidents.
• Level 3, conditional autonomy: Autonomous vehicles of this level are fully
aware of the environment and undertake driving, but may require the driver’s
intervention at any moment. Although the driver does not have to watch the
road, he/she must be able to take control when notified. The limits between
autonomous driving and human control are a little vague. The driver may
need several seconds to intervene and assess the situation, whereas SAE
states that “a few seconds” are enough.
• Level 4, high level of automation: The stand-alone vehicle operates all the
driving functions, but under certain “scenarios”, such as in highway driving,
or when the vehicle moves in a well-mapped area. A Level 4 autonomous
vehicle may experience problems when it has to move to an unknown area.
• Level 5, full autonomy: At this level, the stand-alone vehicle is capable of
handling with ease all circumstances, move under any weather condition as
if it was a human. Sensors provide information about everything and spe-
cialized software allows the autonomous system to operate fully aware of
the environment, without needing prerequisites to function. Level 5 is the
most difficult to achieve, but unfortunately, in the transport sector, anything
less would be a compromise, since security is just as important as efficiency.
Despite the advances in intervehicle communication and in the communi-
cation with the road network, and the advances in artificial intelligence and
expert systems that support autonomous driving solutions, there are still several