Please help why does she keep running off

Chevy has never ran away from me in her life why is it starting now?this is the second time this month this has happened . I asked a friend she said maybe she's lacking exercise but I take all my dogs for a brisk walk morning noon evening and night and Chevy gets let out into the garden whenever she pleases . But I have never have had a problem with her off lead before . She usually comes outside with me when I sit out front and she lies by my chair or follows my daughter around the yard while she plays strangers pass by stray cats and cars pass by and no reaction from Chevy . I had brought her outside with me like any other normal day and out of the blue she took off running and did not respond when I called her. And she always responds to her name . And after that I limited her to her four walks a day and the garden . And just tonight I went to take out the trash and she ran through my legs I called she didn't respond once again to her name .. it is starting to scare me help

Just a quick thought, might she be in heat?

That was my thought as well, has she been spayed yet?

First thing that I thought too

Yes that's what my friend had said but she has beenspayed when she was a pup

Am sorry you're scared n don't really know what to say or suggest to help but could there have been some wild animal around at all, like a fox or something? I hope someone can give advice and help soon, wishing you luck x

Is her behaviour just running, or is she actually bolting away in fear? Just trying to work out what is happening

When it starts its just running then when she don't respond to her name I of course take off after her and once she gets to a certain point she stops dead in her tracks and runs back to me . The part that scares me is she always runs toward the dead end where all houses have fences she can't get far but what worries me she will run off toward the main road one day but why she always hits that point then stops

How old is this dog?

A year and a half