While reviewing my notes and other class materials for week 2 of LIS 712 (History and Development of Public Libraries), I stumbled across this video from 2008 via PBS' POV webpage. (A History of the Bookmobile)
(The history part of the program begins at 1:38.)
Washington Free County Library (Maryland)
Expanded and updated a PowerPoint slide while I was at it.
Public Libraries in the United States Survey. (Institute of Museum and Library Services)