There are multiple ways of viewing current road traffic and route information in Google Maps Navigation (Beta):
Traffic layer
Touch the Layers menu icon then choose Traffic View to see the current traffic conditions for the initial steps of your journey, as well as current traffic conditions for nearby roads.
Route & alternates
Touch Menu > Route & alternates to see your entire journey with traffic conditions appearing over the route, as well as traffic on nearby roads.
Note: The current traffic conditions appear as bands of red, yellow and green along your route. Gray areas mean no traffic information is available for that segment of road.
Time to destination
While traveling along your route, Google Maps Navigation will display the estimated time remaining of your route in the lower-left corner of the screen. The colored dot (either red, yellow, or green) corresponds to the current traffic conditions of your route.
You can also press the time to get a look-ahead view of the current traffic conditions of your route. Press it again or press the Back-to-car button to return to tracking mode.