Global Street Design Guide

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Table of Contents

Global Street Design Guide

Major Intersection: Reclaiming the Corners

The intersection of two major streets can act as both a barrier and a node. Redesigning major intersections requires a critical evaluation of the tools and trade-offs available to make an intersection work better for everyone.

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.

Existing Conditions

In this illustration, a large, one-way street with four travel lanes intersects with a two-way street carrying three lanes in each direction. This intersection is extremely wide and chaotic, with an unbalanced allocation of space between modes. It has long traffic signal cycles.

Designed primarily for motorists, the sidewalks are too narrow or non-existent.

Crossing facilities are grade-separated by overhead foot bridges that significantly increase the travel time for pedestrians and are inaccessible to those facing ambulatory difficulties. Fences along the sidewalk, installed to prevent people from walking on the roadbed and to impede illegal parking, further increase walking distances. These are often utilized by vendors to display goods.

Large corner radii designed to accommodate high-speed turns and inadequate pedestrian refuge islands present a danger to  vulnerable users. Slip lanes at the corners encourage high speeds for motorists turning without having to pause.

Design Guidance

This reconstruction shows the conversion of a large car-oriented intersection into a compact, well-delineated, and safer node.

 Remove pedestrian overpasses and replace them with at-grade crossings. This reduces crossing time and distance, increases  sidewalk space, and makes the pedestrian crossing accessible for all users.

 Reduce turning radii and reclaim space at the corners to safely accommodate high pedestrian volumes. This creates additional  space for transit stops and street vendors.

Install pedestrian refuge islands to reduce crossing distance and provide a protected waiting space.

 Reduce the lane width and extend the central median as a simple, cost-effective measure to improve safety.

 Extend ground markings for cycle lanes through the conflict zone of the intersection, matching the width and positioning of the leading cycle lanes.

Prioritize mass transit to increase the capacity on busy streets. Convert a travel lane in each direction of the two-way street, and one lane of the one-way street, into transit-only lane.

On the one-way street, remove one travel lane to add a parking-protected, two-way cycle track.

On the two-way street, add a raised cycle track on each side of the street, ramping lanes up to meet sidewalk level when they are adjacent to transit stops. Ensure a change in markings to indicate these potential areas of conflict between cyclists and transit riders.

Define travel lanes through markings and reduce their width in order to reduce vehicular speed.

Addis Ababa, Ethiopia. An interim transformation showcasing the principles such as tightening the corner radii, adding appropriate intersection markings and reducing crossing distances.

Adapted by Global Street Design Guide published by Island Press.

Major Intersection: Squaring the Circle

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Major Intersection: Squaring the Circle