Human-sensitive street lights

In Toulouse a form of street light has been installed that dims when no one is around and brigtens up when a pedestrian comes in range. Lights like this could also go far to reduce the light pollution that hides the stars in even modestly-populated areas. One downside I can see is what happens when there are problems with the sensors. I've seen many current street lights with maladjusted photocells that turn off the light when a pair of headlights go by. Maintaining the infrared sensors could become a headache.