Althoug it has been said over and over, and there is a ton of information available on the subject, it is clear that the hubs are ranked on the following, and as you can see traffic is only one consideration:
Amount of traffic - including percentage from reputable sources other than HubPages
The reputation of the Hubber - your Hubber Score and contribution to the community
The response of readers to your hub - including comments, thumbs up, etc.
The uniqueness of content - copying content already available on the web will be penalized