Section 2.2.2 explained different levels of automation in a very general sense. In this section we want to apply these concepts specifically to the automotive domain. Automation that is present in cars already today, found its way into the automobile via driver assistance systems. These sys- tems, integrated with the vehicle, support the driver particularly in safety-critical situations, and provide comfort functions as well and relief the driver from routine tasks (cf. [41]). As opposed to driver information systems, driver assistance systems are able and designed to intervene ac- tively with the control of the vehicle. Complex and sophisticated assistance systems are usually calledadvanced driver assistance systems (ADAS). ADAS are defined by all of the following characteristics [33], p. 4:
– ADAS support the driver in the primary driving task
– ADAS provide active support for lateral and/or longitudinal control with or without warn- ings
– ADAS detect and evaluate the vehicle environment
– ADAS use complex signal processing
– direct interaction between the driver and the system
The mapping of existing driver assistance systems onto the described levels of automation (cf. 2.2.2) is not entirely possible. Most driver assistance systems act only in very specific situa- tions, e.g. warning against a certain danger (e.g. forward collision). Only a few are performing a permanent control task (e.g. cruise control). Therefore, in the automotive domain, the tax- onomies choose a more use-case-related approach for expressing the degree of intervention with the driving task. Usually we distinguish between five degrees of assistance (cf. e.g. [115]):
– Information: The system presents the driver additional, uninterpreted information (e.g.
current position on a map).
– Recommendation: Presenting information to the driver suggesting an action (e.g. low
temperature information or speed limit information implying to adapt speed if too fast).
– Warning: Signals the driver an immediate action is strongly advised in order to avoid a
potentially dangerous situation or collision (e.g. lane departure, forward collision warning).
– Active intervention: The system proactively intervenes in a safety-critical situation with
the vehicle control (e.g. steering to support lane keeping, braking to avoid forward colli- sion).
– Automated control: Long-term activity of the system, it takes over a part of the driving
Primary driving task Driver Assistance System Degree of Assistance Stabilisation
Anti-lock Braking System (ABS) Active intervention Traction Control System Active intervention Electronic Stability Program (ESP ) Active intervention
Manoeuvring
Speed Limit Information Information / Recommendation Cruise Control Automated control
Adaptive Cruise Control (ACC) Automated control Forward Collision Warning (FCW) /
Forward Collision Avoidance (FCA)
Warning / Active intervention Lane Departure Warning Warning Lane Keeping Assist / Support Warning /
Active intervention Park Distance Control (PDC) Information / Warning Park Manoeuvre Assist (PMA) Automated control Night Vision System Information / Warning
Navigation Navigation System
Information / Recommendation Traffic Message Channel (TMC) Information /
Recommendation
Table 2.3: Selection of common driver assistance systems currently available in modern cars and the provided degree of assistance.
Table 2.3 shows an overview of common driver assistance systems currently available in modern cars together with their corresponding degree of assistance (also cf. [68]). All degrees but automated control become active selectively and short-term. In Flemisch’s definition (cf. Fig. 2.7, left) degree 1–4 would be subsumed asassisted. Only with permanent control for a longer period of time (degree 5) it is legitimate to speak of automated driving. Usually only a part of the driving task is automated (longitudinal or lateral control), which is then described as
semi-automated driving. Combined longitudinal and lateral control (speed and heading) is
highly-automated. Fully automated is synonymous to autonomous driving including all parts
of the driving task (stabilisation, manoeuvring and navigation) are completely taken over by automation (cf. 2.2.2). To fulfil this, a car must be able to drive to a pre-set destination using unmodified infrastructure. The paradigm of Conduct-by-Wire [178] automates stabilisation and manoeuvring. The driver issues a manoeuvre request and the automated system performs it. Automated driving involves necessarily the control of the vehicle’s movement. Although there are many automated functions inside the car (automatic windscreen wipers, adaptive headlights, automatically closing the hood of a convertible car in case of rain, etc.), the term ’automated driving’ requires locomotion.
It is important to mention that automated driving cannot be seen without constraints. Even if driving (semi-/highly) automatically, the driver still has the responsibility for his vehicle. This has been stipulated in theVienna Convention on Road Traffic7, a UN treaty signed 1968 in Vienna in order to standardise traffic rules. The Vienna Convention (VC) states in Article 8, paragraph 5:
"Every driver shall at all times be able to control his vehicle or to guide his animals."
This is further specified in Article 13, paragraph 1:
"Every driver of a vehicle shall in all circumstances have his vehicle under control so as to be able to exercise due and proper care and to be at all times in a position to perform all manoeuvres required of him."
Based on today’s legal situation in most countries in the world as stated in the VC, complete automated driving without involving the driver at all would therefore not be permissible on a large scale. The crucial question is, who is responsible in case of an accident: the driver, the car, the car manufacturer, the sensor manufacturer, the programmer? The VC clearly identifies the driver still as the single responsible instance. But there are already efforts undertaken to bring the probably outdated phrasing in the VC up to date for future forms of driving.