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City of Toronto - Curb Radii Design Guidelines

Roadway design engineers in Canada have historically relied on design guides as the basis for
engineering roadways. However, most traditional guidelines were developed decades ago, have
not been substantially revisited, are limited in guidance on urban conditions, and have not always
fully considered all modes of transportation.

To respond to the needs of all road users and improve safety of the most vulnerable users (e.g.,
pedestrians and cyclists), the City of Toronto has developed new and context sensitive Curb Radii
Design Guidelines that are used to determine appropriately sized curb radii at intersection
corners. The Guidelines consider various factors to determine curb radii at each intersection
corner including road classification, truck volumes, expected vehicle types, land use, approach
lane widths, departing lane widths, intersection angle, and presence of bus routes and bike lanes.

At the outset of this project, it was determined that the vast majority of intersection corners in
the City of Toronto were oversized and could be reduced without any significant impacts to
turning vehicles and intersection operations. There are several benefits for vehicles and
pedestrians when oversized curb radii are reduced. These include reduced pedestrian crossing
distances, reduced vehicle turning speeds, improved driver sight angle and increased pedestrian
storage space. . With the drop in manufacturing within the City of Toronto, the conversion of
former industrial land uses to residential land uses, in addition to residential densification, there
has been a decline in the volume of tractor semitrailers. Since a single standard curb radius was
initially constructed at most intersections, many sections of arterial roads with very infrequent
large truck volumes have overdesigned curb radii.

Changing long-standing standards and practices in any large organization or industry is not an
easy feat. As such, several innovative approaches were used to make these Guidelines context
sensitive, practical and easy to apply. Some of these are outlined in this submission.

The City of Toronto Curb Radii Design Guidelines fill a gap in the toolbox of many designers
striving to improve road safety for vulnerable road users. As a pioneer in the field, the guidelines
are influencing how urban areas across Canada rethink the design of our roads from a multimodal
safety perspective.

Author

City of Toronto

Session title

2016 Road Safety Engineering Award

Organizers

Road Safety Standing Committee

Category

Road Safety

Year

2016

Format

Paper

File