Some of the primary features of Advanced Driver Assistance Systems (ADAS) ensure safety, assistance and availability of information to the drivers. Thus these systems are set to revolutionise the future of vehicle development. This paper describes the prospects of Advanced Driver Assistance Systems as well as its limitations and potential risks.
“Advanced Driver Assistance Systems” (ADAS) is frequently used as a generic term for all systems supporting the driver when driving. Driver Assistance Systems are designed to inform the driver, warn or give recommendations in critical situations, or even allow the driver to delegate tasks to the vehicle. They can occasionally, even partly, control the vehicle and enhance the vehicle stability. Driver assistance functions must be examined very carefully regarding their impact on performance, use cases, legal aspects, operability, and their harmonious interaction with other driving functions, as well as their human machine interfaces .
Figure: 1
The kind of assistance - and this represents a further systematisation characteristic - is certainly specified by the degree of assistance. This can reach from the simple information presentation to automatic interferences into the driving action.
In the control loop driver-vehicle-environment, the driver is a system controller.
Human beings play two central roles in offering an approach for assistance:
Stability control systems such as Anti-Lock Braking System (ABS), Dynamic Stability Control (DSC), Electronic Stability Program (ESP) or Electronic Stability Control (ESC) intervene in the area of vehicle stability boundaries in a temporally very short time interval. Consequently, in such situations, the driver - apart from a spontaneous correction - hardly possesses the physical abilities to ensure the stabilisation of the vehicle. Due to his/her limited skills, the average driver is not able to coordinate simultaneous braking of four individual wheels in a way to bring an under or overriding vehicle back to course. The market success of stability systems shows that drivers accept this transparent intervention and permit such condescension by a system, if such assistance systems enhance driving in critical or dangerous situations.
Driver assistance systems on the maneuvering level have the ambition to optimally supply the driver with information, warnings, references, or recommendations on one hand and on the other hand to allow the driver to delegate driving tasks partially or completely. Accordingly, divergent degrees of assistance are possible on this level (see fig. 2).
Figure: 2
The enhancement of a driver's sensory competence happens by supply of helpful information/warnings (e.g. acoustic park assistance, view improvement at night, display of the route map, vibration of the steering wheel during critical approximation to the edge of a lane). Thus, the driver should be able to follow his/her actual driving task more competently and safely.
In the other case the driver consciously transfers parts of his driving task (e.g. the linear tracking) to an automatic control system. The primary intention of these systems is to provide relief to the driver by delegation with a strong focus on comfort aspects. Still the driver must always have the option to override the system or switch it off, if he/she feels it is appropriate.
For example, in contrast to stability control systems, where the requested reaction time is only some milliseconds, driver assistance systems on the maneuvering level are concerned with tasks which require response times of some seconds. Driver assistance systems can be designed to reduce unpleasant tasks or, within limits, to increase the driver's competency.
The intention of ADAS is not to substitute the driver or dismiss him/her from the responsibility. This is neither desired nor feasible. The dream (or rather the nightmare?) of autonomous driving without the driver's effort as shown at the Grand Challenge event in the desert of Nevada still remains limited to lonely desert paths for a long time. The principal reason for this can be identified in the still insufficient reliability of the detection and interpretation of the vehicle environment. While, for example, dynamic stability control systems (DSC) can rely on vehicle-internal physical measurements such as acceleration, wheel spin, yaw rate, or roll angle which are distinguished by high precision and short evaluation times of milliseconds, the interpretation of the vehicle's environment is much more difficult and offers a lower reliability. The RADAR system of an ACC Stop&Go for instance can detect the distance and relative velocity of a preceding vehicle or a standing object with sufficient accuracy. However, whether this object stands as an obstacle in the personal lane, or the vehicle passes the object without a risk of collision, cannot be detected early enough with just the RADAR system alone. A separate detection path like a camera system is necessary. This simple example shows that for the situational interpretation a fusion of many separate detection channels is essential. Yet the system will not be as efficient in interpreting a particular situation as the driver is able to.
The broad implementation of multifunctional assistance systems into the vehicle requires integration expenditures on most divergent levels. The necessary geometrical and electrical integration of numerous components and assemblies are nothing new for a manufacturer. The challenge though is the integration of functions aiming to support the driver in various driving maneuvers and critical situations.
The customer expects a harmonious overall picture regarding the interaction of a multi-functional assistance system with an intuitive and self explaining Human Machine Interface (HMI).
A number of questions arise that have to be clarified far before system introduction into vehicle, e.g.:
An eminent responsibility remains with the vehicle manufacturer considering the possible verifications in driver competency, situation complexity, driver intention, traffic situation etc.
Driver assistance systems are normally offered as individually selectable options. Therefore, each function requires independent sensor technology and a dedicated HMI. This product's strategic premise often collides with the task of a scalable, functionally integrated approach with high economical efficiency - e.g. based on central data fusion units for all available ADAS functions. Under this aspect and the expectation of rising take rates, discussions will move forward on possible equipment packages.
In its volume 2/2006 the German magazine “Auto, Motor und Sport” published an interesting analysis to a partial aspect of the every year’s reader election “The Best Cars 2006”. The question to the readers was: “What will become generally accepted in the future?”
A list was generated from this analysis. On top was the electronic stability program, which delivered a truly triumphal procession. As many as 80% of the readers voted for this driving dynamics system and forecasted good future chances.
The “Adaptive Headlamps” as a driver assistance system which is still relatively easy to communicate, ranked number 6. Such a system can easily be explained and demonstrated to the customer by salespeople in the car companies’ showrooms.
Other assistance systems ranked behind. The “Brake Assistant” finished at number eight, the Adaptive Cruise Control (ACC) system, here wrongly equated with the term driver assistance system, ended up on rank 15. AMS chief editor Bernd Ostmann summarised: “the readers obviously still have no exact conceptions of these new systems, the use is not yet assessable, perhaps there are too high costs, which deter from ordering these features”. Further: “In any case, drivers are also anxious about the new techniques: do I still drive the car on my own? What if the system fails? ”
The question of correct and successful marketing for driver assistance systems no longer employs the marketing departments of vehicle manufacturers alone. How shall a salesperson communicate the benefits of a technically fastidious and cost intensive feature as the ACC, if even specialists need extensive driving time to be able to evaluate specifics of this system? In the future, communication strategists and marketing experts will need to more actively work hand in hand with development engineers and consider how to explain driver assistance systems more easily, and to configure them attractively for a potential customer. Driving simulators, or better yet, driving demonstrators could be effective support tools to explain use cases and to communicate the value and characteristic of the assistance systems, as well as to make situations “experience-able”. Due to its practical considerations, it is not always possible to let drivers learn about all systems within a demonstration car in the normal traffic.
Considering the facts stated in this paper, the question must be raised during the introduction of driver assistance systems: How much ADAS does the customer actually tolerate? Similar to Passive Safety with a refusal of vehicle owners to embrace pyrotechnic “explosives” during the introduction of the first airbag systems, drivers also have to be familiarised with the delegation of driving tasks to the vehicle. This hurdle is best taken, if the driver recognises that the assistance system does not take away tasks that he would rather solve himself, but supports him in his/her duties or automates unpleasant tasks.
Ten Golden Rules of Driver Assistance:
1 - Driver operations to activate and use ADAS and feedback from the car to the driver (switches, buttons, controllers, displays etc.)
Director of Integration, Driver Assistance Systems and Active Safety
