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Based off: Functional Classification Maps from IDOT Home page
Also Getting Around Illinoishas a functional class map that may be easier to pan around on.
US Route and State Route Naming
- In July,2013, all US Hwy XXX have been changed to US-XXX.
- State Rte XXX is being changed to SR-XXX format.
- CR-XXX will be used where applicable. Most have a Primary Street name, so this would only apply to an Alternate Field entry.
FC cross reference
Refer to this chart to determine the road type of a given road based on the functional class.
To use this chart, first determine the functional class of a road, and whether it is a signed, numbered highway in a particular highway system.
Where the column for the road's highway system and the row for the road's functional class meet, you will find the proper road type for that particular road.
A number of examples are given below the chart.
| Highway Systems | |||||||||
|---|---|---|---|---|---|---|---|---|---|
| Interstate | Interstate Business Loop/Spur | US Hwy (incl. some [routes]) | US Hwy BUS, SPUR, LOOP | State Hwy (incl. some special routes) | State Hwy BUS, SPUR[a], LOOP | County Route | Locally-maintained | ||
| example | I-90 E | I-55 Business | US-12 | US-460 Business | SR-22 | SR-400 Loop | CR-15 | Robertson St | |
| F u n c t i o n a l C l a s s |
Interstate | Fw | n/a | n/a | n/a | n/a | n/a | n/a | n/a |
| Freeway | n/a | Fw | Fw | Fw | Fw | Fw | Fw | Fw | |
| Expressway | n/a | Major | Major | Major | Major | Major | Major | Major | |
| Other Principal Arterial | n/a | Major | Major | Major | Major | Major | Major | Major | |
| Minor Arterial | n/a | Major | Major | Minor | Minor | Minor | Minor | Minor | |
| Major Collector | n/a | Major | Major | Minor | Minor | PS | PS | PS | |
| Minor Collector | n/a | Major | Major | Minor | Minor | PS | PS | PS | |
| Local/not mapped | n/a | Major | Major | Minor | Minor | PS | PS | Street | |
^a When a state highway "SPUR" route is used to connect a state highway with another state highway, a US highway, or an Interstate (i.e., when it is used as a connector/CONN route), use the first state highway column.
For example,
- An Interstate Business Loop classified as a Minor Arterial is a Major Highway .
- A US Highway classified as a Minor Arterial is a Major Highway .
- A US Highway Spur route classified as a Minor Arterial is a Minor Highway .
- A State Highway classified as an Other Freeway is a Freeway .
- A State Highway classified as a Collector is a Minor Highway .
- A County Route classified as a Minor Arterial is a Minor Highway .
- A County Route classified as a Collector is a Primary Street
- A locally-maintained road classified as an Other Principal Arterial is a Major Highway .
- A locally-maintained road classified as a Collector is a Primary Street .
| Fw | Freeway |
| Major | Major Highway |
| Minor | Minor Highway |
| PS | Primary Street |
| Street | Street |
Freeways
These are interstates, highways, freeways, toll roads, and expressways that are multi-lane, divided roads with no stops (no traffic lights, exit and entrance from/to the road is through ramps). All roads labeled Interstate on the IDOT Functional Class map. Some IDOT classified Freewway or Expressway may fall in this catagory as well.
Major Highway
Principal arterials are the primary routes for traveling throughout the country, from one city to another, over long distances. Many principal arterials are freeways or expressways, but many others are not.
As a nationwide system, the United States Numbered Highways, or U.S. Highways, system provides a direct links between regions not served by the Interstate Highway System, and as alternatives to Interstate travel in the case of heavy traffic or incident.
In Illinois, the Functional Classification is Other Principal Arterial.
Minor Highways
Minor arterials (or other arterials) are secondary routes for traveling between cities over moderately long distances. Minor or other arterials are classified in Waze as Minor Highways.
In Illinois, these are numbered the state highway system. Roads in these systems are designated and selected by the Illinois State Department of Transportation as part of statewide networks of important travel links between cities and communities of those states. These roads, while of lesser national importance, are nevertheless essential for travel within the state. In Illinois these are designated as Minor Arterial.
Primary Street
Collectors are roads used with medium-low traffic densities which are used to bring traffic from local streets to arterials and vice versa. Collectors are classified in Waze as Primary Streets. Some states designate county routes which are important for travel within a county. These routes serve important functions in a short-distance capacity. On the Illinois Functional Class map, these will be Major Collectors and Minor Collectors.