For more than 80 years, the Institut für Straßenwesen (Institute for Road Traffic – isac) at RWTH University Aachen has been instructing on planning, equipping and operating road traffic systems. There is increasing interest about the psychological aspects of the activity of “driving”. The Institute uses a driving simulator in order to be able to better investigate these aspects. In the interview, Eugen Diner explains how the driving simulator works and how the simulation software PTV Vissim brings working with the simulator even closer to reality.
Compass: RWTH University has long used a driving simulator for its research work. What is the simulator like?
Diner: The driving simulator has a modular structure. The basic physical model is formed by a mock-up, a self-made model. It is an old Fiat Punto dissected in the middle which we have placed in front of a screen. We have also integrated a large monitor behind the B-pillar, i.e. between the front seat and the back bench seat. The study participant takes his place in the car and uses the vehicle as normal: He sees the route to be travelled on the screen in front of him, and things happening behind him in the rear-view mirror. The whole thing is acoustically accompanied by engine noises.
Compass: What is the aim?
Diner: We use the driving simulator to put study participants into a certain situation. The closer to reality it is, the less the study participants will be reminded that they are taking part in an experiment and therefore the better the results of the research will be. The interesting thing is that it does not matter whether signs or houses at the edge of the road are clearer, we just need to create interaction.
Compass: Why is interaction so important?
Diner: If you get the study participants to drive a route in the driving simulator where there is no traffic in their own lane and no oncoming traffic, then the study participants very quickly get the feeling that they are part of a game. One option is to incorporate traffic statically. But then the driver does not interact with the other vehicles and, again, they get the feeling that they are part of a test setup. Through the connection to PTV Vissim, we have succeeded in integrating dynamic surrounding traffic into the test setup.
Compass: So our simulation software therefore ensures good interaction between the vehicle being driven by the study participant and the surrounding traffic?
Diner: That’s right. The key point is that if the study participant sees that the surrounding traffic reacts to him then he behaves accordingly and also reacts to the other road users. His braking and accelerating behaviour is quite different to what could be produced with static traffic. It would be reckless to say that you can completely recreate reality, but we have come much closer to doing so with Vissim.
Compass: From theory to practice – what kind of research projects use the driving simulator?
Diner: It is always used whenever we need to investigate measures and their effects on the behaviour of road users. In the same way as micro-simulation, the key advantage here is being able to compare and investigate different options. Comprehensive investigations of the psychological aspects of traffic can mainly only be carried out in the driving simulator, because tests in reality would not be possible or would be dangerous. A current example is the problem of people driving the wrong way. We have investigated the behaviour of road users when they meet someone driving the wrong way or when they “unconsciously” drive the wrong way themselves. The investigations were carried out with several groups of participants, and various scenarios were researched. In order to do this, we let the drivers go the “wrong” way so that they ended up in the oncoming traffic. Building on this, we also investigated possible warning concepts.
Compass: What warning concepts did you investigate?
Diner: In relation to preventing drivers going the wrong way at a junction, we compared two warning concepts and one comparison option (no warning). The road users were made aware of their “error” by a red flashing reflector post or using an acoustic and visual warning signal.
Compass: And what is the ideal warning concept?
Diner: The ideal warning concept was found to be a combination of acoustic and visual warning from a navigation system. Due to the fact that, thankfully, road users only end up in this situation extremely rarely, they need additional supporting instructions as well as a warning. The question “What do I do now?” must be answered as quickly as possible in this extremely dangerous situation. The navigation system has proved to be a suitable and quickly available means of communication in this case.