Puppy training tips please?

Its a lot easier just to let my dog out the front door because the back door is downstairs, but i cant because she doesnt listen to me. she doesnt run as soon as she gets out but she likes to roam around and sniff and wont listen when i call her name. its like she just ignores me. then when i walk towards her she starts trotting away. im not afraid of her getting lost because she has tags on but i am really worried that she will get hit by a car. i really need some help.