Bremer Straßenbahn AG (BSAG) is introducing a newly developed AI-based safety system designed to identify potential threats more quickly on its trams. The system, known as “AI Watch”, was developed in collaboration with Bremen-based AI company Just Add AI and is regarded as unique in this form across Germany. A pilot phase has been under way since April 2025. By the end of 2026, around one third of the tram fleet is expected to be equipped with the system, with further vehicles to follow from 2027 onwards.
Real-Time Analysis On Board
At almost 37 metres in length, a tram carriage cannot be fully monitored by the driver at all times. “AI Watch” addresses this challenge by analysing interior camera footage in real time and identifying potential threat situations directly on board the vehicle. The software operates on an independent computer installed within the tram, ensuring that all data processing takes place locally.
Data protection has been a central consideration in the system’s development. Video footage is neither stored nor used to further train the AI model. In addition, passengers are automatically pixelated before the footage is processed, ensuring that individuals cannot be identified.
Training with Realistic Scenarios
To ensure reliable detection of incidents, the AI was trained using specially staged and realistic video sequences. These included simulated physical altercations and instances of aggressive behaviour within the vehicle. When “AI Watch” identifies a potential threat, the relevant live camera image is transmitted to the BSAG control centre. Staff there assess the situation and, if necessary, request assistance.
Strengthening Safety in Public Transport
The introduction of the system is seen by political representatives as an important contribution to improving the perception of safety in public transport. Özlem Ünsal, Bremen’s Senator for Construction, Mobility and Urban Development, has described the project as a key component in protecting both passengers and employees. In light of changing perceptions of safety across Germany, she emphasised the importance of ensuring that public spaces remain secure and trustworthy.
Thorsten Harder, Technical Board Member at BSAG, also underlined the significance of the initiative. Although serious incidents within the BSAG network are rare, the AI tool further enhances safety for passengers and staff alike. The long-term solution is intended to strengthen the resilience and attractiveness of public transport. According to the company, feedback from drivers has so far been consistently positive.
Federal Funding Support
The development of the system and the installation in one third of the tram fleet involve costs of approximately €500,000. Eighty per cent of this amount is funded by the Bundesministerium für Verkehr under its ‘Digitalisation of Municipal Transport Systems’ programme, which promotes sustainable mobility solutions in both urban and rural areas.
Several Hours of Video Material for Training
Nearly four hours of video footage were produced in recent months to train “AI Watch”. The recordings depict realistic situations inside tram vehicles, with all individuals pixelated: https://cld.bsag.de/bsagcld/index.php/s/Ld95H6HZfY7fEJc. In operation, the software visually highlights detected incidents, for example by marking them with a coloured frame, thereby enabling the control centre to assess situations quickly and efficiently.
With “AI Watch”, BSAG and its technology partner are positioning themselves as pioneers in the deployment of privacy-compliant AI solutions in public transport—an approach that is now attracting interest both nationally and internationally.
20.02.2026
