In most smart phones google maps compass mode doesn't work properly in cars. To get to compass mode open maps and hit icon on lower right corner twice. Once is follow me mode and twice is compass mode. The icon should turn blue on one click then change to blue compass icon on second click. In compass mode maps should Orient to the direction you are heading so your direction is always up. (similar to navigation but with no destination entered and traffic conditions still visible if you choose traffic layer).

This mode doesn't work in samsung phones because compass won't hold calibration and metal in car affects detection of North. I wonder if it works properly in a nexus on a long drive?

Beamed from my Galaxy Note 3