ATTRIBUTE INFORMATION: 11 Descriptive Fields (highways.pdf):

Name -- The descriptive name for the road segment

Source -- The original source of the road feature.  S - State Supplied Digital Data; U - USGS Digital Line Graphs;  T - US Census Tiger/Line files;  D - Digitized          from State supplied maps;  M - Military Supplied data

Sign1 -- A composite field that identifies the type, sign route numbers, and a qualifier.

type:  (blank) - not signed,  I - Interstate,  U - US Route,  S - State Route,  O - Off-Interstate Business Marker,  C - County Route,  T - Township,  M - Municipal,  P - Parkway or Forest Route Marker, N - None of the above 

qualifier:  (blank) - No qualifier, not signed, or not applicable,  A - Alternate Route,  B - Business Route,  P - Bypass,  S - Spur,  L - Loop,  F - Proposed (future),  D - Temporary (detour),  T - Truck Route,  N - None of the above

Sign2 -- Secondary identifier including the type, sign route numbers, and a qualifier. 

Sign3 -- A composite field for a third identifier including the type, sign route numbers, and a qualifier.

Miles -- The length of the road segment in miles. (Number)

Km -- The length of the road segment in kilometers. (Number)

Toll -- 	0 - Not A Toll Road,  1 - Toll Road

Lanes -- Number of through lanes in both directions.

Median -- 0 - Unknown; 1 - Divided Highway; 2 - Undivided Highway

Class -- Assigned functional class description.