Pictures of the Future      Fall 2005

Equipping Cars to Understand their Environments

Interview with Hans-Georg Metzler

Hans-Georg Metzler (57) is Head of the Laboratory for Active Safety and Driver Assistance Systems at DaimlerChrysler in Stuttgart. An electrical engineer, Metzler’s goal is to make cars so intelligent that they can recognize hazards—without burdening drivers with too much technology

Today’s cars feature parking assistants, electronic stability programs (ESP) and even systems to warn against impending collisions with the vehicle in front. How much more intelligence can there be in cars?

Metzler:There’s a simple answer to that. If we’re talking about comfort, we’ll only develop a system when it’s clear that it reduces the burden on drivers. But as far as safety’s concerned, there aren’t any compromises. ESP, ABS and air bags have brought substantial improvements in road safety—improvements that would have been inconceivable without such systems.

What benefits will future driver assistance systems generate?

Metzler: The purpose of such systems should be to help drivers, so that they can fully concentrate on driving. These systems already prevent accidents just by helping to reduce the stress of driving. We’ve shown this in tests conceived to monitor the driver’s condition at the wheel. Here, the stress levels are calculated on the basis of brain pattern measurements.

To what extent might the electronic systems of the future infringe on driver autonomy?

Metzler: We’re not talking about taking responsibility or the authority to make decisions away from drivers. Drivers will remain in control. The degree of intervention depends on the concrete situation. A system should inform or warn a driver and possibly even intervene at the last moment by, for example, executing an emergency stop—a solution we’re currently implementing for trucks. Developing the kind of technology that can comprehend and assess such complex situations will remain an exciting research challenge for the coming years. It’s already clear that future driver assistance systems will be capable of understanding the full vehicle environment. A whole range of components, including radar systems, video cameras and digital maps, will provide them with the information required for this task. And some onboard systems will in fact be one step ahead of the driver. Examples include systems capable of detecting other road users who are invisible to the naked eye. Imaging radar, for example, will monitor blind spots as well as the vehicle’s surroundings at time or when visibility is poor.

What kinds of things will future cars inform and warn us about?

Metzler: Cars will be able to provide us with greater information about the immediate traffic situation. The greater the volume of traffic on our roads, the more we’re going to see stressful or potentially dangerous situations. In the future, for example, a system will warn us of a traffic jam up ahead, long before we actually see the flashing warning or tail lights. Another system will be able to recognize sharp curves and road signs warning of hazards even when it’s dark and foggy. Yet another advanced system will be able to assess whether a slow-moving vehicle up ahead is in fact preparing to move into the passing lane and pass someone in front.

That seems fairly complicated. How will you ensure that people and their cars can still understand one another?

Metzler: The word "understand" makes it sound as if we can equip our assistance systems with human capabilities. That’s utopian, of course. Our goal is to put together all the information into a consistent picture in order to analyze potential dangers. We want to create a system that not only monitors road situations, but also warns drivers and even intervenes where necessary. That means it must also be able to assess the danger potential of a situation that has been identified.

How are sensors supposed to make intelligent decisions?

Metzler: Individually, sensors are inadequate to the task. But when combined, they provide a very full picture of the situation. The key concept here is sensor fusion. Combining a long-range, narrowbeam sensor with a short-range, wide-angle sensor obviously increases the area covered. Sensor fusion plays a key role in enhancing the precision of an assistance system and extending its functionality. To achieve this, you can combine different data sources almost at will. For example, you can ascertain the course of the road ahead using not only video analysis, but also a digital map to extract data related to the radius of curves ahead. This would mean that a car would be capable of recognizing a dangerous sharp curve in advance. In such a situation, it could either reduce engine power appropriately or warn the driver that he or she is driving too fast. In the future, assistance systems equipped with a range of sensors will be able to monitor and interpret the complete vehicle environment correctly.

Can you give an example?

Metzler: Sure. Take a situation in which a vehicle crosses an intersection in front of you, for instance. Assessing the potential dangers in such a situation is an extremely complex process. On the other hand, if you’re driving on an access road that leads onto a highway, then the cars rushing by at an angle don’t constitute a danger. The car needs to be able to recognize the difference between these situations. And there are thousands of similar examples. They all illustrate how difficult it is to map reality using technical systems. The only way to overcome such challenges is to combine sensor data in an intelligent manner.

Given such challenges, what do you expect cars to realistically be able to do in ten to fifteen years?

Metzler: To get closer to realizing the vision of accident-free driving, we need assistance systems that can put together as complete a picture as possible of the traffic situation and then recognize impending danger. This is exactly what the cars of the future will be capable of. They will therefore provide drivers with much more support than today’s vehicles do. We’ve already taken a decisive step toward the goal of halving the number of road fatalities by the year 2010 in Europe. Take the example of short-range radar. In the future, short-range radar systems could help prevent the majority of rear-end collisions. DaimlerChrysler will soon become the world’s first automaker to offer this technology in a vehicle featuring a system based on 24-GHz short-range radars.

                                                                                               Interview by Tim Schröder