ZF Lifetec develops seat belt with infrared signature
ZF Lifetec combines different yarns with distinct spectral properties in the belt webbing. Together, they create a signal that infrared cameras can evaluate.
ZF Lifetec
ZF Lifetec has integrated an infrared signature into seat belt webbing so in-cabin cameras can distinguish it from clothing, skin and seat surfaces. The technology is intended to detect incorrect belt routing more precisely and provide better input for occupant safety systems.
ZF Lifetec has developed a seat belt with an integrated infrared signature designed to make belt routing more visible to in-cabin cameras. The supplier plans to start series production of the “Infrared Belt” in August 2026 and intends the technology for every seating position.
The aim is to give driver and occupant monitoring systems more reliable information about whether a person is wearing the belt correctly. Unlike a conventional buckle switch, the camera-based approach is intended to identify how the webbing runs across the body and flag misuse that could reduce restraint effectiveness.
How does the infrared signature work?
ZF Lifetec combines different yarns with distinct spectral properties in the belt webbing. Together, they create a signal that infrared cameras can evaluate. This is intended to make the belt stand out from clothing, skin and seat surfaces, while reducing the influence of changing light conditions inside the cabin.
The camera can then follow the path of the webbing across the occupant’s body and determine its position. The assessment remains the responsibility of the vehicle manufacturer’s recognition algorithms. Using the camera data, they could establish whether the belt is routed over the shoulder, underneath the arm or behind the occupant’s back.
This places the development within a wider move towards seatbelt detection inside the vehicle interior. Camera and depth data are increasingly being considered both for detecting occupants and for supporting restraint decisions based on how safety equipment is actually used.
Why are buckle sensors not enough?
Traditional buckle sensors mainly establish whether the latch plate has been inserted. They do not reveal whether the belt follows the intended path across the torso. ZF Lifetec’s infrared webbing is designed to close this information gap without replacing the existing buckle sensor.
The supplier also sees advantages over standard colour cameras. Reflections, similar colours and fluctuating illumination can interfere with optical classification. The new method instead relies on the material properties of the belt in the infrared spectrum. This should provide a more stable signal and a clearer basis for software-based interpretation.
What is driving demand for better occupant data?
Driver and occupant monitoring is becoming increasingly relevant to regulation and vehicle safety ratings. The European Union has introduced requirements for driver drowsiness warnings and advanced distraction warnings in stages. These rules define functions and technical performance, but do not generally prescribe one particular camera technology.
Euro NCAP is also placing greater emphasis on the real-world use of restraint systems and accurate occupant detection. Interior monitoring can provide a basis for adapting restraint functions and assessing seat occupancy more precisely. This convergence of in-cabin sensing and software is turning the vehicle interior into an important source of safety-critical data.
For vehicle manufacturers, this raises the integration challenge across cameras, sensors, software and passive safety systems. A belt that produces a clearly distinguishable optical signal could improve input quality. Whether the approach proves robust across clothing, seating positions and everyday operating conditions will become clearer once series production begins.
