The LUMIOS MkIII measures the level of luminance, or brightness, created by natural light at the tunnel portals to ensure that the visual perception of drivers is maintained, both day and night, by avoiding sudden variations in lighting levels and potential “black hole effect” when entering and exiting a tunnel. The LUMIOS MkIII can also be used for the measurement of luminance within the tunnel.


  • Measurement of luminance, or brightness, created by natural light at the tunnel portals
  • CIE Approved measurement of L20
  • Variable viewing angle within a range of 10 to 40º (factory preset)
  • Silicon photo diode, Vλ filtered for spectral response close to that of the average human eye
  • Rugged 316 stainless steel construction with IP66 protection rating
  • Heated window and enclosure
  • Self-contained intelligent analyser for direct connection to host controller
  • Suitable for measurement of luminance within the tunnel


  • Designed specifically for monitoring tunnel portals
  • Rugged design to withstand extremes of weather conditions
  • Simple installation and mounting
  • Optional wash-wipe facility to minimise maintenance requirements
  • Flexible integration options


For further information and technical specifications about this product please download a product brochure alternatively contact us via phone or email and a member of our team will be happy to help.

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We have developed a good working relationship and received excellent service throughout the installation and commissioning period. Since then, the instruments have performed very well.

Clive Dyche A.C.M.I.
Medway Tunnels, UK

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