My first suggestion -- NEVER let her off leash until she is more trustworthy. Also never let her off leash close to a road, it's asking for heartbreak.
My first suggestion would be to buy her a REALLY long leash. I practice with Jackson on a 50 foot training lead that I found on eBay. I let him go out all the 50 feet, explore, sniff, etc, and then say "Jackson, come!" and I
always give him a treat when he comes to me. Never punish them when you get them, even if you're mad that they just ran away.
It would also be good to take her to a large field, not close to a road, that's fenced in (dog park, baseball field, etc) and practice in an area where she's safe. Also, chasing them usually makes them run more. Typically running the opposite direction makes them be like "huh? where is she going?" or doing something odd, like you sitting on the ground, it makes you more appealing to them because you're doing something different. When you're chasing them, they think it's a game.
Another good thing to teach is the "stay" command. Practice having her stay at the door so every time that door is open, she doesn't bolt. Start with staying for 2 seconds with the door open, then move to 5 seconds, etc.
I suggest watching It's Me or the Dog on Animal Planet or Dog Whisperer on National Geographic.
Good luck!
