The database is indexed and links to color scans of the pages. The registrations appear to have been printed on an ongoing basis and organized numerically within each volume.
The entry shown in this image comes from April of 1919 and is for "A. Trautfether."
A. apparently resided at 48 N. Orange in Medford, Oregon--in Jackson County. He had a Packard with motor number 48193, it was a 1914 model, 2-ton truck ("tk 2 tn").
Users of this database are encouraged to read the prefatory materials accompanying each volume.
Part of that prefatory material is included as a part of this blog post.
An interesting database for those with Oregon connections. Individuals who do not appear in city directories may appear in this listing and it may be possible to track their changes in residence using this database.
It can be searched here for those with an Ancestry.com subscription.
Now to find out who A. Trautfether is--which reminds me that names can get spelled a variety of ways.