For city streets to meet the needs and demands of everyone using them, intersections—both large and small—need to function as safely and efficiently as possible. Good intersection design, however, goes beyond making streets safer. Well-designed intersections use street space to bring people together and invigorate a city, while making traffic more intuitive, seamless, and predictable for those passing through.
– From NACTO Urban Street Design Guide
The intersection of two major streets can act as both a barrier and a node. Redesigning major intersections requires designers to critically evaluate the tools and trade-offs available to make an intersection work better for everyone.
While shorter cycle lengths, compact design, and pedestrian safety islands are all desirable components of a multi-modal intersection, the tradeoffs inherent in each make these difficult to achieve simultaneously. Weigh intersection geometry, signal timing, and traffic volumes to formulate a design that clarifies the hierarchy of street users, while enhancing the safety and legibility of the intersection.
– From NACTO Urban Street Design Guide
Intersections of major and minor streets often lack the same level of definition, safety, and clarity as major intersections. Bicyclists and pedestrians, though legally permitted to cross at these locations, are implicitly discouraged from doing so through design. Vehicles often fail to yield at these locations and have few design cues to suggest they should.
Where major streets meet minor streets, define the transition in street type and context using “gateway” treatments such as curb extensions, raised crossings, and tight curb radii. Use design elements so that people turning from the major to the minor street become aware they are entering a slow speed environment.
– From NACTO Urban Street Design Guide
Raised intersections create a safe, slow-speed crossing and public space at minor intersections. Similar to speed humps and other vertical speed control elements, they reinforce slow speeds and encourage motorists to yield to pedestrians at the crosswalk.
– From NACTO Urban Street Design Guide
Mini roundabouts and neighborhood traffic circles lower speeds at minor intersection crossings and are an ideal treatment for uncontrolled intersections.
Mini roundabouts may be installed using simple markings or raised islands, but are best applied in conjunction with plantings that beautify the street and the surrounding neighborhood. Careful attention should be paid to the available lane width and turning radius used with traffic circles.
