Functional Classification Data
According to the Indiana Department of Transportation, Functional Classification is described as the following.
Functional classification is the process by which streets and highways are grouped into classes, or systems, according to the character of service they are intended to provide. Basic to this process is the recognition that individual roads and streets do not serve travel independently in any major way. Rather, most travel involves movement through a network of roads. It becomes necessary then to determine how this travel can be channelized within the network in a logical and efficient manner. Functional classification defines the nature of this channelization process by defining the part that any particular road or street should play in serving the flow of trips through a highway network. (FHWA Functional Classification Guidelines)
The easiest resource to use for Functional Classification data in Indiana is the Indiana Roadway Inventory site. To show Functional Class information, go to the Map Contents box in the lower left corner, click the checkmark next to Functional Class, and uncheck any other items that you would not want to see.
If you'd prefer offline PDFs, the Indiana Department of Transportation has maps for major cities and all counties in Indiana.