I do that too!!!!!!!!!!! It can get really absurd. For me, it's not always just leg muscles. Sometimes I click my molars together on the left or right side.

sometimes i cross my legs and make my left leg do the right and the right leg do the left ^o^

I do this & I've talked to other people who do to. I often pretend i'm (or some animal like a cat is) jumping between patches of grass or telephone poles.

I don't twitch my legs, though I do sometimes imagine I'm a ninja running through the grass field along side the road.

I do something similar to this, I kinda lift my butt muscles off the seat when i'm driving over a shadow made by a telephone pole!

omg, i never specifically thought about it before, but i just realized that i do those things all the time too

Perhaps you're connected to the 'boxes' atop the poles--muscles behave with electrical impulses from the brain--why wouldn't a surge of electrical impulses OUTSIDE the brain make them react? Not abnormal--perhaps just highly sensitive or oversaturated with electricity[!!!]
Does anything happen when you pass anything else--or do you only notice it when you're relatively relaxed and yer brain is more or less 'open' to incursions?

I do that or I used to alot when I was a kid. Id just bite a little on either side of my tounge if we passed a driveway. Id have pressure on the side that the driveway was on for the exact time it was next to the car. Same thing with telephone poles, and other stuff.

this made me laugh alot lol i can picture you doing it

i lift my feet when i'm in a car or on the bus and i'm passing another vehical, but only if i'm passing an odd nuber of vehicals. but i worry about my sanity, so that might not be reassuring. :S

when im walking and a car drives past i jump

OH MY GOSH!
I do that too! Actually, I tilt my head between poles or those traffic cones, or lines on the road, whatever is there, I tilt th eupper part of my body to seem like I'm dodging them. It's so weird! I never knew anyone else did that!

When I'm in a car I'll usually imagine someone running along side, jumping on all the walls and swinging from the lampposts.

if had a driving license, this is totally the kind of thing i'd do.

Also the ninja thing o/

yeah, i do that too, especially on a bus

I do it, or like twitch em like jumping over driveways, onto grass.

I thought i was the only i knew who did that, haha.

i do the tounge bite thing
or move gum from one side to the other
its like a game

I do this sometimes as well. Usually in the gaps and I twitch my butt muscles sometimes.

I do that too

i do all of those tjings it helps pass the time on loooooooooooong road trips