Roadway Classifications
For ease of use, the guidelines are categorized based on NIRPC roadway classifications, and the Complete Streets guidelines and recommendations of GI to utilize are based on roadway class. The roadway classifications these guidelines focus on are listed below. See NIRPC Interactive Functional Class Map page for overview and road locations Northwest Indiana Draft Functional Class (carto.com).
- Principal (Primary) Arterial - The largest designation, typically multi-lane roadways with high traffic volumes (over 20,000 ADT) and high speeds (35 mph to 50 mph), ideally spaced at 2- to 4-mile intervals (National Association of City Transportation Officials). These are major throughways that provide the best connectivity from one place to another but are not controlled access. (NIRPC Interactive Functional Class)
- Minor (Secondary) Arterial - Typically multi-lane roadways with moderately high traffic volumes (over 10,000 ADT) and moderately high speeds (30 mph to 45 mph), ideally spaced a 1- to 2-mile intervals (National Association of City Transportation Officials). Minor arterials also hold through traffic but are best for connecting closer areas. They generally have slower speed limits and more curb cuts (NIRPC Interactive Functional Class).
- Collector - Typically two-lane or multi-lane, two-way streets with moderate traffic volumes (over 5,000 ADT) and moderate speeds (25 mph to 35 mph), ideally spaced at quarter-mile to 1-mile intervals (National Association of City Transportation Officials). Major Collectors collect local traffic and have better connectivity than local roads. Minor collects are similar to Major Collectors, except they connect less roads than a Major Collector would (NIRPC Interactive Functional Class).
- Local Streets - Typically two-lane, two-way roads with low traffic volumes (under 5,000 ADT) and moderate speeds (20 mph to 25 mph), ideally spaced at 200- to 600-foot intervals. Local streets often are not marked with center dividing lines and located around residential or business-oriented areas.
- Intersections/Roundabouts – Traffic circles or junctions where multiple roadways meet or cross.
- Pedestrian & Alleys – This includes alleyways or bike lanes within streets and walkways in the adjacent right-of-way.