Freeway lighting suggestion

I wonder how many kilometres of lighted freeways there are in the world where the lights are left on all night?

I wonder how much energy is wasted when there is no traffic at 3am for example?

How about a traffic sensing Ohm which turns street lighting on and off (or dims it) rather than leaving the lights on all night?

There would be a market not only for the sensors / energy monitors, but also the light bulbs themselves!

I see a sensor with an app, so when a car is detected at the start of the freeway, all the lights go on for the next kilometer. After 500 metres, there is another sensor. If the car is alone, the lights for the first 500 metres are switched off when the second sensor is reached, and the lights for another 500 metres further down the road are turned on.

Of course, it uses an app so you can select to leave a light permanently on or dimmed every kilometre or whatever.

Energy usage is monitored, and the savings calculated.