NEW YORK CIT Y PL AZA PROGRAM
NEW YORK CIT Y PL AZA PROGRAM
Intersections
91 Intersection Design Principles
For city streets to meet the needs and demands of
92 Principles
94 Major Intersections
everyone using them, intersections—both large and small—
96 Intersections of Major and
need to function as safely and efficiently as possible.
Minor Streets
98 Raised Intersections
Good intersection design, however, goes beyond making
99 Mini Roundabout
streets safer. Well-designed intersections use street space
100 Complex Intersections
to bring people together and invigorate a city, while
102 Complex Intersection Analysis 104 Redesign
making traffic more intuitive, seamless, and predictable for those passing through.
Intersection Whether while driving, shopping, walking, or lingering,
intersections are a focal point of activity and decision,
Design
and thus are critical parts of the city streetscape and
Principles transportation network. Intersections account for the most
serious conflicts between pedestrians, bicyclists, and drivers, but also present opportunities to reduce crashes when designed carefully. Good intersection design can tap civic and economic potential, infusing overbuilt or under utilized spaces with street life.
Intersection design should facilitate visibility and predictability for all users, creating an environment in which complex movements feel safe, easy, and intuitive. Their design should promote eye contact between all street users, engendering a streetscape in which pedestrians, drivers, and bicyclists are aware of one another and can effectively share space.
IN T E RS E C T I O N S
Principles
Intersections are the most challenging aspect of street design in an urban environment. Capacity constraints at these pinch points in the roadway network govern the width of roadways as they pass through them. People on foot may avoid difficult crossings or subject themselves or their children to considerable risks while crossing a street at a poorly designed intersection. The principles outlined here enable practitioners to build intersections as meeting points that function well for everyone using them.
PRIN CIPL E S
Design Intersections to Be as
Integrate Time and Space Compact as Possible
Analyze Intersections as Part of a
Reconfiguring intersections in time Compact intersections reduce pedes-
Network, not in Isolation
(through signalization) provides an trian exposure, slow traffic near
Solutions may be found at the corridor
alternative to widening intersections conflict points, and increase visibility
or network level. Tradeoffs can often
to solve delay or congestion. Integrate for all users. Limit the addition of
be made between the intersection and
spatial and temporal intersection dedicated turn lanes and pockets,
the network in terms of traffic volume
design strategies throughout a project. and remove slip lanes where possible. Break large, complex intersections into a series of smaller intersections. Use existing pedestrian behaviors and desire lines to dictate design.
and capacity.
Intersections Are Shared Spaces
Utilize Excess Space as Public Space
Design for the Future
The goal of intersection design is
Design should account for existing not strictly to reduce the number of
Interim public plazas and low-cost
and future land uses as well as conflicts for a given user at a select
safety improvements should be used
projected and induced demand for location, but to create a space in
to enhance public life and mitigate
all users. Land uses and pedestrian which users are mutually aware of
safety concerns in the near term.
generators play an equally important one another and visible and predic-
role in making decisions about table in their actions to reduce the
intersections and relate directly to overall rate and severity of crashes.
the desires and objectives of the surrounding community.
EXISTING CONDITIONS
1 Large intersections like that shown above are often over-
designed and difficult for both moto rists and pedestrians to manage. Channelized right turns and other features create unsafe, high-speed turns.
Evaluate whether or not all travel lanes are absolutely necessary through corri- dor analysis, and assess the impact of removing a lane in the traffic network.
At large intersections, bicyclists and pedestrians suffer from long exposure times and multileg crossings. Cycle lengths of 120 seconds or more and 2-stage crossings further exacerbate delay. Large corner radii and inadequate pedestrian safety islands designed to accommodate high-speed turns fail to convey safety within a busy intersection.
The intersection of 2 major streets can act as both a barrier and a node. Redesigning major intersections requires designers to critically evaluate the tools and tradeoffs 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.