Global Street Design Guide Intersections Intersection Analysis

Global Street Design Guide

Intersection Analysis

The following design process takes a sample complex intersection and details how to understand its existing function, analyze movement, identify opportunities, and

create a new design. Driving this process is the underlying need to let land use, community desires, and usage determine solutions.

Context

Understand the context within which the intersection functions. Analyze its urban design qualities and document specific gathering places, landmarks, transit stations, and other drivers of activity. Engage the public in this process, allowing safety concerns and community visions to drive the ultimate redesign.

Pedestrian Activity

Document how pedestrians use and activate the intersection as a public space. Where are people gathering, sitting, and talking? What activities are they engaged in? Which public spaces attract people and which do not? Where do people actually cross the street? In urban locations with continual activity, this step can often be accomplished by 15–30 minutes of observation.

Transit and Cycle Activity

Assess the volume and movement of cyclists as part of the planned and existing cycling network. Document bus headways and volumes, as well as the placement and location of bus stops and other transit facilities. Make note of all other modes of collective transport, their boarding and alighting locations, and facilities.

Vehicle Volumes

Map vehicle movements and turns to understand how motorists use the intersection. Overlay volume data to illustrate the relative importance of each movement, looking for low-volume turning movements, in particular. Pair this with observation and understanding of the local planning context and how the street fits into the overall traffic network.

Signalization

Plot the signal phases to show how the intersection flows. Obtain phasing data from the appropriate agency, or create a general timing plan, ascertained with a stopwatch. Note whether pedestrian and vehicle signals are fixed or actuated. Observe how well the phases match volumes, how people comply, and when signals give priority to drivers, cyclists, or pedestrians.

Geometry, Signals,
Signs, and Markings

Survey the intersection’s dynamic conditions, or how people are meant to move through the junction based upon existing markings and geometry.

Adapted by Global Street Design Guide published by Island Press.