Apparatus (10) for monitoring vehicle (V) usage on a roadway (H). An AC light source (12) comprises either an incandescent or gas discharge light source. The light source has a detectable AC ripple in its output. The light source is mounted or installed above the roadway surface on a conventional...http://www.google.fr/patents/US5764163?utm_source=gb-gplus-shareBrevet US5764163 - Non-imaging electro-optic vehicle sensor apparatus utilizing variance in reflectance
Non-imaging electro-optic vehicle sensor apparatus utilizing variance in ...
