We used Dynamap data from TeleAtlas (Global Crossroads, Boston,
MA) for 2000 as the base road network configuration. The highway
category was based on combining two categories from the Dynamap
database: (1) primary roadways without limited access (Feature Class
Code — FCC A1); and (2) primary roadways with limited-access or
state highways (FCC A2). Major roadways were created from the
Dynamap secondary and connecting roadway data category (FCC A3).
The population data and corresponding boundary files were at the census
tract level from U.S. Census Bureau for 2000.