Dear 100 Hour Board,
Streetlights are not motion-sensored, are they? It seems like every time I go-a-walking up 9th east at night, the streetlights turn off as I pass them. Maybe they're all the same age and burn out at the same time, but it's kind of a weird experience when you're walking past and see a flash, only to discover that the light above you just went out...and then the next and the next ones too. What's the deal?
-Tired of walking around in the dark
Ever heard of a deluminator? I think that is your problem. Either you're using one without realizing it, (Do you have a silver cigarette lighter, perchance?) or you have a friend/enemy with one who is trying to drive you crazy.
Wait... you're not trying to stalk Ron Weasley while he's doing secret Auror business, are you? That would definitely explain a lot. But be careful, friend. You're getting yourself into some dangerous territory. And I'm willing to bet that you're a Muggle, too, and don't even have a wand. This is not wise. Very not wise. Get out while you still have a chance.
Really, I think it's just a perception thing. You probably walk by dozens of street lights every day, but when nothing happens, you take no note of them. Since you only take note of the street lights which go out as you walk by, you end up with a perception that the street lights are responding to your presence, when in fact they do no such thing.
Incidentally, it would be a very poor design that made street lights turn off as people walk by. While I'm not going to make any universal declaration that no motion-sensitive street lamps exist anywhere in the world, I will argue that if they do exist, they're going to be the type that light up as soon as they sense motion, they'll light up and stay lit until no motion has been sensed for a predetermined amount of time. And I'll also argue that even that isn't a very good design, as animals could just as easily set off the lights as could humans or cars, effectively eliminating any power savings you're likely to get by turning off the street lamp. Also note that if these street lamps are designed for use on city roads, they'll have to look for motion well in advance, as cars tend to move pretty quickly.
In light of all that, I'm going to say that your street lamps definitely are not motion sensitive.
I think we've all considered that we're the cause of it at one time or another (I had a mission companion convinced), but it's more than most likely that it's just chance. Street lights "cycle" a lot and you notice it when you're near them. You should read this.