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Sign Retrorelfectivity

Traffic Signs Retroreflectivity


By using a 4K Digital Video System calibrated to the human eye instead of using retroreflectivity meters actual sign performance can be measured in terms of the true sign/road markings interaction with the driver where other factors, such as sign orientation and obstructions, can be taken into consideration.

Through research Impulse Geophysics Ltd have created algorithms to convert the grey-scale measurements from the images to Retroreflectivity Luminance (mcd.m-2.lx-1).

As always with video systems, they allow a greater degree of quality assurance rather than relying on discrete measures, which in this case are taken from retroreflectivity meters.


The sign/roadmarking images are stored and archived. With more and more traffic on the UK’s roads and hardshoulder running it is no longer possible to carry out the traditional methods due to safety concerns.

Not only is Traffic Speed Retroreflectivity cost effective it is inherently safe and produces consistent results to allow comparisons year on year. The system is designed to target maintenance using the intervention levels from the DMRB



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