Fibre optic sensors for traffic monitoring applications

Pekka Suopajärvi, Riku Pennala, Mikko Heikkinen, Pentti Karioja, Veijo Lyöri, Risto Myllylä, Seppo Nissilä, Harri Kopola, Heikki Suni

    Research output: Chapter in Book/Report/Conference proceedingConference article in proceedingsScientificpeer-review

    14 Citations (Scopus)


    A novel fibre optic sensors for traffic monitoring applications are presented. They are useful for monitoring the traffic entering and leaving guarded areas, counting traffic on public roads as well as in determining lane occupancy at traffic lights. When installing sensor arrays, the sensors may also be used to provide additional information: measure the speed, wheel base of a vehicle and also to determine the number of axles and vehicle type. The sensors are based on optical fibre or cable, installed inside the asphalt layer of the road, to measure compression or vibrations near the road surface. Two sensor principles were used. One based on the microbending effect and another that utilises the speckle phenomenon. In both cases the whole length of the fibre acts as a sensor. The microbending sensor requires a special fibre and special set-up, whereas in the speckle sensor a standard cable may be used. Both sensor types were tested in field applications where the harsh environment, especially the heat, sets great demands on installation. In these experiments, speed and vehicle type measurements were carried out with good results. In the paper, we will discuss the advantages and disadvantages of both sensor types and present some field test results. We will also show the benefits of these particular fibre optic sensors over traditional sensors.

    Original languageEnglish
    Title of host publicationProceedings of SPIE
    Subtitle of host publicationSmart Structures and Materials 1998 Smart Systems for Bridges, Structures, and Highways
    PublisherInternational Society for Optics and Photonics SPIE
    Number of pages8
    Publication statusPublished - 1998
    MoE publication typeNot Eligible
    Event5th Annual International Symposium on Smart Structures and Materials : Smart Systems for Bridges, Structures, and Highways - San Diego, United States
    Duration: 4 Mar 19985 Mar 1998

    Publication series

    SeriesProceedings of SPIE


    Conference5th Annual International Symposium on Smart Structures and Materials
    Country/TerritoryUnited States
    CitySan Diego


    • Microbending
    • Speckle
    • Vehicle detection
    • Vibration


    Dive into the research topics of 'Fibre optic sensors for traffic monitoring applications'. Together they form a unique fingerprint.

    Cite this