Roads in TIP are not simply routes between destinations. They are part of the structure that determines where settlement, commerce, industry, and later suburban growth occur.
The network ranges from inherited local roads and the mile-grid landscape to county highways, major arterials, U.S. and state routes, expressways, and interstate corridors. Each belongs to a different period of regional development and serves a different role.
Many important corridors predate the landscapes that now surround them.
Early routes followed practical crossings, dry ground, settlement paths, and connections between emerging communities. As the region developed, some were improved into plank roads, county highways, or major arterials. The Public Land Survey System imposed another powerful order on northern Illinois, creating the mile-based framework that remains visible in much of the modern road system.
Later metropolitan development inherited those lines.
Not every road belongs to the same system or serves the same purpose. State, county, township, and municipal control creates differences in maintenance, design, jurisdiction, and regional importance.
A local street primarily organizes access within a neighborhood. An arterial connects municipalities and commercial districts. County highways bind together larger suburban and rural areas. Controlled-access highways reshape development at an entirely different scale, concentrating growth around interchanges and creating new patterns of logistics, retail, employment, and suburban expansion.
The hierarchy matters because access is uneven—and uneven access creates different places.
Infrastructure changes the value and function of the land around it.
An old highway may become a dense local commercial corridor after through traffic moves elsewhere. A new interchange can create a logistics district where farmland previously dominated. A bypass can shift development away from one municipality while creating opportunity for another.
For this reason, roads in TIP are both transportation infrastructure and historical geography. They record how the region moved, where it invested, and which places became connected—or bypassed—over time.