Have you ever heard of this lighting system?

Question

I've heard there is a lighting system applied on some roads which is able to control the lights installed on the sides of the road.

Whenever there is no car on the road it keep the lights on with the least power,in fact it turns the lights down and

when there is a car entering on one of the slip roads,it switches on the lights for a certain time but this time with the most

power.It keeps them on for 2 or 3 min and by this way, it helps to save the energy.

Many thanks!

Answer 1

Just like the signal tracking system used in railways (where signal to indicate the train to stop/slow down if any other train is crossing in areas having only one railway line. This is to avoid head-on collisions. The same mechanism must be used to roads, especially highways, interstates and after night hours where the roads are not trafficated always.

Answer 2

I have applied lightings based on motion movement -  which we use frequently in buildings to save energy. For example, we all know building escape routes have to be lighted at all times, but we know that seldom the route is used. So, to compromise between safety and energy savings, lightings are provided WIth motion detectors, which will light up when the sensor has detected motion due to the movement of people. This concept is also very common in toilets. Similar concepts are applied in roads as well.