I have had this happen maybe a dozen times, I was pretty sure they switch the lights out for the thermal cameras to track you, but I once did it on command, I could just feel that I had done it on purpose. Usually it's just during a sexual energy peak or something.

Doesn't really seem to have much rhyme or reason, no real purpose.

I do think they have thermal cameras on the lightposts though, and they sometimes switch the lights off because the light interferes with the infrared.

Nowdays though the lights switch on and off so much, because they are trying to save energy or something, hard to tell.

the lights only come on now when a car drives down the road, if no traffic they switch off so they are switching on and off all the time.