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Design Guidance
Figure 6.11 Recommended Roadway Typical Characteristics
Roadway
Classification
Number of Lanes*
Daily Traffic Volume*
Access Control*
Land Use Service*
Posted Speeds*
Freeway
Four or Greater
40,000 or Greater
High
None
50mph or Greater
Land Use:
Adjacent land uses tend towards basic retail, food services, distribution, warehousing, and commercial types. Generally not
suitable for noise- and vibration-sensitive uses.
Median Treatment:
Nearly always, and frequently in excess of 40’ in width often with variable heights between the two road directions.
Pedestrian/Cyclist Accommodations:
None, although breakdown lanes of 8’ or wider are typically present, along with additional “soft”
shoulder leading to an open ditch line for drainage in rural areas. Bridges should be wide enough to accommodate pedestrian sidewalks
on at least one side of the road, and 14’ outside lanes for cyclists. Minimizing free-flow right turns and narrowing the intersections also
aid in pedestrian and cyclist movements and safety. To-edge of property greenway connections are required; off-property pedestrian
improvements may also be requested to connect to schools, parks, or other pedestrian destinations.
Intersection Treatments:
No at-grade intersections, only ramps are allowed. At the end of the ramp tying to a surface street, signals are
present in urban and STOP controls for the ramps in rural areas.
Major Thoroughfare
Two to Seven
20,000 or Greater
Moderate
Low
45mph to 55mph
Land Use:
Adjacent land uses typically include retail shopping, banking, and other service-oriented industries. Recommend clustering these
uses around a cross-street (Minor Thoroughfare) and limiting accesses for driveways to at least 1,000 feet between major generators and
cross-streets outside activity centers. Inside the activity centers the minimum recommended separation is 600’.
Median Treatment:
Recommended, with a minimum width of 22’ to accommodate significant plantings as well as future turn lanes at
intersections.
Pedestrian/Cyclist Accommodations:
At higher volumes (over 25,000 vpd), bicycle lanes of 4’ to 6’ are recommended. At volumes higher
than 35,000vpd and speeds of 45mph, off-road treatments are desirable for cyclists. Sidewalks of 5’ width (minimum) on both sides of the
street are required, as are audible countdown pedestrian signals at street intersections. To-edge of property greenway connections are
required; off-property pedestrian improvements may also be requested to connect to schools, parks, or other pedestrian destinations.
Intersection Treatments:
Extend turning lanes before adding a second turn lane in dense urban areas near high-walk zones and activity
centers. Include pedestrian refuges at intersections; pedestrian-activated signals at major crossings and greenway crossings; and disallow
high-speed right-turning movement designs.
Minor Thoroughfare
Two to Five
5,000 to 40,000
Fair
Moderate
35mph to 45mph
Land Use:
Adjacent land uses may include limited residential driveways, but no new residential driveways should be permitted. Typical uses
include neighborhood retail, although the number of driveways and cross-streets should be sharply limited to allow the efficient movement
from local streets to the Major Thoroughfares.
Median Treatment:
Recommended minimum width of 22’ to accommodate significant plantings as well as future turn lanes at
intersections.
Pedestrian/Cyclist Accommodations:
Typical treatments include wide outside lanes (14’ min.) or bicycle lanes (4’ to 6’) where there are
fewer cross-streets and driveways, and continuous sidewalks, audible pedestrian signals, and crosswalks at all intersections. To-edge of
property greenway connections are required; off-property pedestrian improvements may also be requested to connect to schools, parks,
or other pedestrian destinations.
Intersection Treatments:
Intersections should be designed to minimize walking distances at the lower-level cross-street by providing smaller
curb radii (30’) and curb extensions in activity centers. Minimum driveway spacing no less than 400’, and intersection clearance at 100’ from
driveway tangent to cross-street tangent.
Collector
Two to Three
1,000 to 20,000
Low
Moderate-High
25mph to 40mph
Land Use:
Encourage development off side streets only, limiting the number of driveways on the main street. Very limited, low-intensity service
businesses at major street intersections only are encouraged. Street trees are encouraged in the buffer to create a height-to-width ratio of
3:2 to 3:1, wherever possible. May be in a residential or nonresidential area.
Median Treatment:
Medians of 10’ to 22’ may be provided depending on the nature of the street relative to its position inside an activity
center or other higher-density environment.
Pedestrian/Cyclist Accommodations:
Wide outside lanes or sharrows are common accommodations for cyclists, the latter occurring where
on-street parking is present. Pedestrian accommodations are intense in activity centers, including furniture, scaled lighting, and continuous
sidewalks on both sides of the street as well as crosswalks and pedestrian signals at intersections with Major or Minor Thoroughfares. To-edge
of property greenway connections are required; larger private developments may be required to construct off-site pedestrian improvements
to reach major pedestrian destinations such as parks, schools, and other facilities within ¼-mile.
Intersection Treatments:
Intersections should be designed to minimize walking distances at the lower-level cross-street by providing smaller
curb radii (25’ to 30’) and curb extensions in activity centers. Separation between driveways to an intersection should be kept to 100’
minimum, and spacing between driveways 250’ minimum.
Local
Two to Three
50 to 12,000
Very Low
High
15mph to 35mph
Land Use:
Nearly exclusively for residential uses, typically single-family driveways andmultiple, attached units (e.g., duplexes and townhomes).
The only commercial uses would be allowable home-based or auxiliary services.
Median Treatment:
Typically, none.
Pedestrian/Cyclist Accommodations:
Typically, no bicycle accommodations are needed unless traffic volumes reach the higher end of this
range (wide outside lanes of 14’); pedestrians should be accommodated with sidewalks on both sides of the developed street completed
prior to final inspection. To-edge of property greenway connections are required of new developments; larger private developments may
be required to construct off-site pedestrian improvements to reach major pedestrian destinations such as parks, schools, and other facilities
within ¼-mile.
Intersection Treatments:
Intersections are designed with the pedestrian in mind and curb radii no larger than 20’. Ladder-style crosswalk
markings may be required for intersections with Minor and Major Thoroughfares.
Alleyways
Two
10 to 250
Very Low
Very High
5mph to 10mph
Land Use:
Connects residential rear yards to parking areas and trash pick-up points, and connects street fronts to rear-yard parking lots in
commercial and downtown districts.
Median Treatment:
None; total roadway width is typically only 12’ to 14’ with 5’ on each side of the road.
Pedestrian/Cyclist Accommodations:
Landscaping, pedestrian furniture, and lighting are key elements of great alleyways. Sidewalks are not
typically necessary, but the narrow width prohibits on-street parking.
Intersection Treatments:
Not applicable.
Main Street
Two to Three
250 to 10,000
Very Low
Very High
15mph to 25mph
Land Use:
A range of civic uses, attached residential units, and street-level retail are common. Zero or narrow setbacks and sideyards,
emphasis on massing, voids, and façade elements are critical to obtain a 3:2 height-to-width ratio along the street.
Median Treatment:
Frequently, 10’ to 22’ planted medians are present, although narrower streets are more in keeping with the design of main
streets in North Carolina and allow better pedestrian access.
Pedestrian/Cyclist Accommodations:
Very high intensity, with street furniture, pedestrian-scaled lighting, wide (10’ minimum) sidewalks and
wide (8’ minimum) planted swales or inside curb extrusions (“bulb-outs”) are commonplace. Design details like crosswalks, audible pedestrian
signalization, on-sidewalk dining/sales; bicycle parking (post-and-loop) and other treatments are made at a detailed level during a design
or redesign phase.
Intersection Treatments:
The walkability of these areas is important – any break in the continuity of building frontage, streetscaping, or
other elements is perceived by the user as an end to the main street. Intersections typically feature curb extrusions, simulated paving stone
crosswalks, and limited or no string-mounted signal heads to further enhance the main street atmosphere. Landscaped and well-lit alleys
complement the architectural style of the environment.
*Typical values, not hard definitions.