Changing unit of measure from degrees to meters in QGIS?

You have to change the Coordinate Reference System of the project; QGIS won't do that when you load a shape file.

Go to: settings->Project Properties->Coordinate Reference System (CRS) and search for your projection.

Although WGS84 and NAD83 both refer to datums not projections. If you want to project your TIGER data, I would be inclined to use either a UTM zone, or a US-wide projection if you're dealing with large areas.