Why did the guinea hen cross the road?

We got some gunea hens this year, and for the most part they've been great.  So far, everything I'd heard is true:
1) They do, indeed, kill and eat snakes!
2) They raise quite a racket when anything weird happens. (We call them "nature's car alarm".)  Sometimes this is annoying, but we haven't lost any chickens to predators this year!
3) They get along fine with chickens and even wild turkeys (though they do tend to follow the latter off the property).
4) I don't know how well they do on ticks, but our area is currently experiencing a locust outbreak, and they certainly love those!  They are getting fa-at!
5) They are definitely more wild-minded than chickens and roam all over the place.

It's that last one I'm having the most problem with.  For the most part they can free range around our property and the fields nexdoor and behind and we don't mind.  The problem is they keep ranging in the front yard and crossing the road.  I'm worried they're going to get themselves hit by a car.

I love keeping them free-range for the locust (and snake) issues mentioned above, but does anybody have an idea how I can discourage them from going near the road?

Nope. They will do whatever dumb things they want. They will fly right over a 6 foot fence. Nothing short of a bird run with a cover will contain them. I had to give up on them entirely because I live on a busy state highway and I didn't want to be responsible for a traffic accident. Sorry, I'm usually more positive!

In my lifetime I have seen lots of guinea hens alongside of a road or the highway.

So why did the guinea hen cross the road?

Was the grass green on the other side or maybe a swarm of bugs they could munch.