The movie is called Rest Stop. Made in 2006.

Sounds like a rippoff of the rohland dahl story in "Tale of the unexpected"

Definitely not Wolf Creek 2 or TCM 2003. Still to recheck Hush though.

I am not sure if this has been suggested yet, but could it be The Texas Chainsaw Massacre (2003)???

Wolf Creek 2 has a part like this, but it might be a guy not a girl x

I'll take a look and post my findings lol.

Sometimes its the movie that the original poster doesn't think it is, that turns out to be the answer.

Hush (2016) is the copycat movie of Mischief Night (2014)
Hush (2008) is the british road horror.
Seen both movies. But I didn't remember a scene in Hush (2008) where the girl goes to a small cottage house, but as someone stated above, she did. So I will need to rewatch it.

There are two recent movies called Hush. Hush (2016) Im pretty certain doesnt have a scene where she runs anywhere near a road or to someone else' house. In this one, the main character is deaf and stays in her home the entire time. This is a horror.
Theres' a Gywneth Paltrow movie made in the late 1990s called Hush. I havent seen it. This one is more of a thriller.

Hmmmm. Hold the phone. I think I need to rewatch Hush.

Every detail matches almost exactly with Hush except there being a m/f couple not just a woman, so if I hadn't seen your first line I would've said it's that!
In Hush they "rescue" a woman who turns out to be an accomplice and it's her who cuts the phone line.
I hope you find it, I want to see it now!
What about
White Settlers (2014)
?
Or
In Fear (2013)
Or (long-shot):
Octane (2003)
Seems like a female-led version of Duel but with an occult spin.

Not reclaim.
And AnonymusCritic. Which movie is that?

The one where a girl leaves the group in search for help, finds a house and asks to use the telephone, the old woman says her husband is sleeping in the other room and goes to make tea, but when the girl looks in the other room the old man is dead in the arm chair, then runs out the backdoor?
I can see the scene clearly in mind but I cant seem to place it right now, let me know if it is the same one you are thinking of and I will try to find it for you?
Edit: I searched high and low, I can not find the title again, thought it might be
Bloodlines (2007)
but can seems to find a copy to check

Reclaim (2014)
?

Not Breakdown. I watched that last week.

ok longshot shot since you haven't found it yet
Breakdown (1997)
End of line

And once we solve it, we will remember the days when we couldn't solve it.

Obviously not, as no one has solved it yet.
I'll let you know when I come-up with a new signature,
.

Nope not that. The movie I am thinking of is pretty popular.

Small Town Folk ?
http://www.imdb.com/board/10478265/
We spared no expense
Si tu veux éviter un malheur, ne jette pas de chips a ton chauffeur

It's not High Tensions, WC2 or Road Games.
I sort of recall more victims, but she was the one who briefly escaped. The country slip road where she hid reminded me of the North of England, so it could have been a British movie. But that's not for sure.
I may be wrong but the part where the elderly woman found out the phone line was cut, she found her husband dead in the other room as he was killed by the killer. Damn! this is annoying me. It's almost at the tip of my tongue!

And the girl is the only victim or is there a group ? She survive or she die ?
We spared no expense
Si tu veux éviter un malheur, ne jette pas de chips a ton chauffeur

Sure it's not a combo of
Road Train
and
WC2
? How about
Road Games
?
I'll let you know when I come-up with a new signature,
.

Never seen it, but could it be
High Tension
? Some say it's similar.
I'll let you know when I come-up with a new signature,
.