AKTIV (completed)

The interaction of intelligent vehicle systems and intelligent infrastructure units is the focus of the AKTIV-VM (Traffic Management) project. This novel kind of team work will create new modes of co-operation between automotive industry, road network operators and the ICT sector. But “Cooperation in traffic” also means a stronger interaction of technical processes which will be enabled by use of new technologies, software and new communication media.

The Institute of Traffic Engineering and Logistics works on following subprojects:

• Cooperative Traffic Signal (leading charge)
• Situation-Responsive Driving
• Network Optimizer

The traffic flow in road networks with level intersections and thus the traffic quality and efficiency as well as the resulting economic costs are significantly influenced by the control systems of the traffic signal systems (LSA). With suitable control strategies, it is possible to switch green waves for main routes and thus to bundle the strongest traffic flows on the reserved network, to reduce stops and travel times and to minimize emissions.

This potential could be better exploited if data on the traffic flow in the extended local environment or on the approaches to the intersection were also available in the traffic signal control system. In vehicles with navigation systems, precisely this data is available in principle. The driver would now have to be motivated to pass on this data to the traffic signal system, e.g., via a WLAN connection. In return, the traffic light can provide the driver with information on the remaining time to the next green or red or on the optimal speed in the green wave via a PDA.

The aim of the research and development work planned in the "Cooperative Traffic Signal System" subproject is to demonstrate and test the potential of cooperative interaction at traffic signal-controlled intersections by means of prototype developments and demonstrations in a real environment, especially on detour routes in the downstream road network. The work of the department focuses on:

• the collaboration on the functional interface specification,
• the simulation-based development of control algorithms,
• the development of a PDA-based driver interface and
• the execution of test drives for the collection of empirical data.

An example application for displaying the vehicle's location in the green wave is shown in Video 3 .

An example application for displaying the remaining shift times until the phase change and the position of the vehicle in the green wave shows the time-lapse recorded drive (Video 1) through a section of the route.

Technologies for optimizing traffic flow and predictive, cooperative driving in special situations are the goals of the "incident-adaptive driving" application. The detection of the local traffic situation by the vehicles and the exchange of information between vehicles and infrastructure improve the performance of the road network in critical situations such as road works. The processing of this information in the vehicle systems leads to the optimal use of the available capacities on the route.

In support of the application "incident-adaptive driving", the department is researching the methodological basis for significantly improving the precision of microscopic traffic situation determination with the aid of so-called floating car observers (FCO). These are vehicles that observe oncoming traffic and report their vehicle density distribution to other vehicles or to a control center.

The work of the department includes:

• the creation of a simulation and development environment to support FCO algorithm development and evaluation,
• the simulation-based development of control algorithms,
• the interpretation of the microscopic traffic situation based on FCO data, and
• the determination of the potential of the FCO approach in cooperative systems.

An example application for two-way traffic detection using FCO is shown in Video 4.

In the "network optimizer", all information about the current traffic situation is collected in a control center. This information is evaluated and converted into a coordinated package of measures and information. Infrastructure facilities such as variable message signs are supplied with information directly. The distribution of the information to the road users takes place in close interaction with the application "information platform". Within the scope of the intended cooperation, information will not only flow from the "public partner" to the "private partner", as is common today, but in both directions.

In the event of disruptions on the highways, the secondary network will take care of rerouting traffic. However, in order to optimize traffic control in the overall network, there is usually a lack of adequate equipment with recording devices for determining the current capacity reserve.  One possibility for increasing the database in the secondary network is to derive capacity-describing parameters from mobile observation of oncoming traffic using so-called floating car observers (FCO).

In this context, the work of the department addresses the following points:

• Methodology and algorithm development for traffic position estimation from FCO data,
• Fusion of FCO data with centralized data and
• Hazard potential estimation based on FCO data.