Collision Avoidance and Optimization of Traffic Flow as an Approach for a Smart City Aalen, Germany

Written by Christoph Cammin and Alice Kirchheim

In the last decades, road traffic significantly increased in many regions. As part of sustainable urban areas, the improvement of safety as well as the optimization of traffic flow are important challenges for road mobility. The new mobile communications standard 5G, which is currently being rolled out, is being promoted with a variety of improvements that also address the transport sector. As one component of a smart city approach, a proposed solution to increase road traffic safety and to optimize the traffic flow by means of using 5G is currently being developed and deployed in the city of Aalen, Germany, as part of the "5G-trAAffic" project.


Road transport is an important aspect of future developments for climate-friendly mobility. Besides the environmental aspects in the context of sustainable traffic, the need for mobility (both people and goods / materials) must be met in a generally resource-efficient and long-term manner. This also includes using space for transport economically and efficiently, as this is very limited, especially in urban areas. Furthermore, only safe road traffic can be sustainable, as safety prevents personal injury and material damage.

In the last decades, the number of registered passenger cars has increased and is now around 48.5 million in Germany [1]. Urban road traffic comprises of many different road users like heavy trucks, busses, individual cars, motorbikes, (E-)bikes, scooters, and pedestrians. The later are among the vulnerable road users (VRUs), whose safety and protection on the road is a particular social objective. Even though national and international programs are established to reduce the number of accidents, the “Vision Zero” [e.g., 2] is still very challenging. Especially the increase of safety at intersections is highly topical, as confirmed by a recent campaign and competition in the United States [3]. Furthermore, traffic flow optimization is not only necessary due to increased road traffic. For example, it is obvious that ambulances and emergency vehicles of the police and fire departments must be prioritized in order to achieve societal goals and tasks, such as the protection of human lives. Besides that, the prioritization of public transport or specific road user groups, such as unmotorized VRUs, can help to make them more attractive and thus lead to a shift in mobility towards more climate-friendly and sustainable traffic.

In parallel, the mobile communication standard 5G will be available in large regions within the next years. In contract to its predecessor standards, it is advertised as “one-fits-all” communication standard with significantly enhanced and new features like network slicing, ultra-reliable low-latency communication, enhanced V2X (vehicle-to-everything) functionalities and hence improved mobile edge cloud communication possibilities. Furthermore, newer releases of 5G shall incorporate high precision positioning services, from which many traffic-related applications can have a benefit.

Solution Approach of “5G-trAAffic” in the City of Aalen, Germany

In order to move forward with the sustainable goals in the areas of road safety and traffic flow optimization, it is first necessary to know the situation of the traffic in real time. In this context, both the microscopic scale, especially at accident-prone locations such as intersections or driveways, as well as a larger overview are relevant. Exemplary, the following questions must be clarified "which road users are on the verge of a collision and should be warned", "what is the status of the individual traffic lights", "on which traffic axes is there currently a high level of congestion and how can this be circumvented?".

In the "5G-trAAffic" project, a hybrid approach is used that relies on both additional infrastructure and interaction with road users via smartphones. Since it can be assumed that not all vehicles will be equipped with comprehensive sensor technology such as that required for autonomous driving in the next few years, and since such sensor technology is hardly feasible for VRUs, appropriate infrastructure-based sensor technology will have to be used to detect traffic situations. In addition to the testing of radar sensors, the focus is on special cameras, which are cost-effectively available for these tasks. These have integrated image analysis for data protection-compliant recording of the situation, for example through internal classification of road users, counting and trajectory calculation, so that no personal live images need to be processed further [e.g., 4].

In addition, a special smartphone app is being developed that will enable integrated data fusion to determine the location of participants as precisely as possible, even with currently implemented releases of 5G networks, in order to improve situational awareness. Future 5G networks based on newer releases will likely incorporate data-privacy conform positioning services with significantly increased precision natively. Today, cellular networks already provide the capability to derive the current traffic load in a precise location-resolved manner, which can be used for traffic control [e.g., 5, 6].


The corresponding actuator technology is equally important. For prioritization of individual road users and control traffic flow, it must be possible to influence the traffic control systems and traffic lights. In the area of safety enhancement, the installation of warning lights and acoustic warning devices is planned in this project in addition to the output of warning messages via the smartphone apps. Vehicles are planned to be directly integrated via roadside units. Via roadside units, appropriately equipped vehicles are directly integration in the communication. The integration of driving assistance systems like automatic brake assistants in the event of imminent accidents is planned for future developments.


As part of the real-world testing, some of the intersections with the highest traffic load and accident-hotspots in the city of Aalen will be equipped with necessary infrastructure within the next few months. In parallel, workshops are planned on the economic aspects of possibilities (e.g., social benefits, cost of additional infrastructure and its operation) as well as to increase public acceptance. In this way, an attempt is being made to implement a traffic concept that is sustainable from various aspects: in addition to reducing emissions through intelligent traffic control, it is also intended to make more effective use of existing roads and traffic areas and to increase safety.


This article contains ideas of the paper [7], in which further details are presented. This work is conducted within the project “5G-trAAffic” (FKZ: 45FGU116), funded by the Federal Ministry for Digital and Transport (Bundesministerium für Digitales und Verkehr (BMDV)). The authors thank all those involved in the project for their support and for the excellent cooperation.


[1] Statista, “Autos in Deutschland 2022,” (last access: 03.08.2023). [Online]. Available: htps://

[2] U.S. Department of Transporta􀆟on – Federal Highway Administration, “Zero Deaths and Safe System“, (last access: 04.08.2023). [Online]. Available: htps://

[3] U.S. Department of Transportation, “Intersection Safety Challenge – From Conceptualization to Initial Testing”, (last access: 04.08.2023). [Online]. Available: htps://

[4] Bernard Gruppe ZT GmbH, “BERNARD Mobility Analyser”, (last access: 04.08.2023). [Online]. Available: htps://

[5] Senozon AG, “Senozon-Wegetabelle”, (last access: 04.08.2023). [Online]. Available: htps://

[6] Telefonica Germany GmbH & Co. OHG, “So bewegt sich Deutschland” [engl. “How Germany moves“], (last access: 04.08.2023). [Online]. Available: htps://

[7] C. Cammin et al., "Concept for a Real-Time IoT-Architecture for Collision Avoidance in Smart Cities based on the 5G Mobile Technology," 2023 IEEE International Conference on Omni-layer Intelligent Systems (COINS), Berlin, Germany, 2023, pp. 1-7, doi: 10.1109/COINS57856.2023.10189240

To view all articles in this issue, please go to January 2024 eNewsletter. For a downloadable copy, please visit the IEEE Smart Cities Resource Center. 

Christoph Cammin is an IEEE Member who received the B.Sc. and M.Sc. degrees in electrical engineering from TUHH, Hamburg, Germany, in 2010 and 2014, respectively. Since 2014, he has been a Research Assistant with the Institute for Electrical Measurement Engineering, Helmut Schmidt University, University of Federal Armed Forces Hamburg, Germany. His research interests include the conceptual design and realization of wireless communication systems and test procedures, especially for industrial use. He is a member of WG 16 “Wireless” of IEC TC65/SC65C and active in the standardization of IO-Link Wireless and the corresponding test specification. 
Alice Kirchheim
Alice Kirchheim researches and teaches in the area of ​​planning and designing logistics systems. Her focus is on developing solutions for the autonomization of logistical handling, transport and transshipment processes. Alice Kirchheim completed her studies at the Technical University of Hamburg-Harburg. After graduating as a computer engineer, she first worked at the Bremen Institute for Production and Logistics at the University of Bremen and later at Reutlingen University as a research assistant. She wrote her dissertation on the detection of piece goods for automatic unloading from load carriers. In the period from 2013 to 2019, Alice Kirchheim worked in various companies in the KION Group in various positions in the sales of manual and automatic logistics systems. She then worked as a professor at Aalen University. Since March 2021 she has been setting up the professorship “Technology of Logistics Systems”.

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