Sensor Line Technology

Everything began in 1996 with the innovative idea of company founder Fred Motzko to detect pressure by light and the first use of fiber optic technology in traffic applications. The applications of this technology are diverse, in road traffic as well as in the rail traffic sector.

About us

A brilliant idea
With endless

The principle of Sensor Line’s fiber optic sensors is as simple as ingenious: under load, the optical transmittance decreases. These changes are detected by an opto-electronic interface and then transformed into signals for traffic data processing.


  • Cheapest permanent sensor installation on the market
  • No mechanical parts
  • Adapts to pavement contour
  • Optimized embedding materials from Sensor Line
  • Light-weight and compact sensor implementation
  • Minimum sensitivity to lateral pressure
  • Ultra-fast, true DC response
  • Outstanding trigger accuracy


An optical fiber has a glass core surrounded by a cladding of lower refractive index. Light traveling inside the core cannot enter the cladding but rather is reflected without any loss. However, guiding light over long distances in this manner requires the fiber to be even-shaped and straight and the refractive index to be very uniform. Stressing the fiber at one point not only causes a kink but also creates changes in the refractive index, thus severely violating both these requirements. Light then escapes from the fiber core. This loss can be measured as a decrease in the optical power arriving at the fiber’s end. This is the principle used inside of Sensor Line’s fiber optic sensors. Unlike other fiber optical sensing principles, it does not require a specially treated fiber or any additional optical components.

A constant quantity of light is being guided along an optical fiber. At moderate curvatures light loss is hardly noticeable. Below a certain bend radius light loss grows dramatically. Light exits due to “microbending”. The quantity of remaining light varies according to the magnitude of the “microbending” effect and can be easily measured with a simple detector.

Explore the possibilities

Sensor Line fiber optic technology is as fascinating as it is simple. The technically advanced products are individually configurable and offer a wide range of applications in the areas of road traffic and rail traffic.

Sensor Line is now Quarterhill.

Quarterhill was launched to fast-forward the transportation industry into a safer, smarter, and more digitally-connected future. Starting soon will transport you to

Thank you for joining us on this exciting journey.

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