Vectorize map from google maps

I would only try auto-tracing the image if I was in a time crunch. I'm not a big fan of auto-tracing filters since the results are rarely ever clean. 

You'll get the cleanest results by locking the map image on one layer and then building new line strokes over the top of the roads on other layers. You can adjust the thickness of the lines, change the color, etc. You can expand the line strokes into closed editable shapes to add things like outlining effects. Or you can duplicate the line strokes on other layers to change colors and thickness to create outlining effects that way. Text can be added down the centerline of the path for street labels.

The process sounds complicated but it's not really all that difficult. And there really isn't a whole lot of details to vectorize in the map extraction image you posted. One other thing to consider: map imagery is usually copyrighted. I would be very hesitant to copy imagery from a maps service verbatim, be it a pixel-based screen grab or something that was auto-traced. A clean vector copy derived from an existing map can be customized with different colors, line thicknesses and various stylings to avoid copyright issues.