North American cities have been making huge leaps in creating
safe places to bike in recent years. The National Association of City
Transportation Officials (NACTO) recently published the Urban Bikeway Design
Guide to describe the best practices that can be used to improve conditions for
cycling and includes a section on bicycle-specific signals. Bicycle-specific
traffic signals are used at intersections with conventional signals to
specifically control cyclists’ movement and were recently reported on by USA Today. Though use of bicycle-specific signals are
limited by the US Manual on Uniform
Traffic Control Devices (MUTCD) there is still considerable experience with
bicycle-specific signals in North America.
 |
The
morning rush on the Broadway Bridge in Portland, OR. Signals controlling motor
vehicles, bicycles and streetcar keep orderly flow. The photo inset shows the detail
of the bicycle signal head. Photo P.
Koonce
|
In a soon to be published paper in the TRB’s Transportation
Research Record, researchers at Portland State University—in collaboration with
engineers from the Portland Bureau of Transportation and the Oregon Department
of Transportation—summarize the results of a recent state-of-the-practice
review related to bicycle-specific signals. The review included two components:
1) a review of related engineering guidance documents:
·
Manual on
Uniform Traffic Control Devices (MUTCD) (FHWA, 2009)
·
Traffic Signal
Guidelines for Bicycles (Transportation Association of Canada (TAC), 2004)
·
Manual of
Uniform Traffic Control Devices for Canada, 2008 update (TAC, 2008)
·
Design Manual
for Bicycle Traffic (CROW, 2007)
and 2) a survey sent to jurisdictions with known
bicycle-specific signals. Survey
responses were received from 15 of the 21 jurisdictions, representing 63
intersections which contained a total of 149 separate bicycle-specific signal
heads. Jurisdictions included in the survey are shown as black boxes within the
figure:
 |
| Jurisdictions identified with bicycle-specific signals and survey respondents. Note numbers following the “:” denote the number of reported signal heads at that location, jurisdictions with a ‘U’ value did not respond to the survey. |
The paper summarizes both physical and operational design
guidance. Physical elements reviewed include details about the suggested size
of lens, the use of bicycle insignia within the lens, color and presence of
backplates, and placement of the signal head. The review of the operational
elements include details about the bicycle-specific signal’s detection,
phasing, restricted movements for other modes, accompanying signage, and
intervals for cyclists to safely cross the intersection. Overall, while there
were minor differences between the guidance documents, the guidance was
generally consistent.
This survey requested detailed engineering aspects about each
jurisdiction’s bicycle-specific signal that they were operating, the topics of
which were previously mentioned (placement, mounting height, lens diameter,
backplate and housing color, type of actuation, interval times, use of louvers,
and performance). The survey of practice found a variety of design elements:
lens size, use of insignia, utilization of louvers, mounting location, and the
means to designate that the signal head is for bicyclists. These elements could
have significant impact on bicyclist and motorist comprehension, as well as the
ability to utilize the bicycle signal head in a variety of intersection
configurations. Some consensus appears on the use of the lens insignia and
accompanying signage. Another part of the survey asked for motivating reasons
as to why the jurisdiction had decided to install a bicycle-specific signal at
each respective intersection, allowing multiple reasons to be cited. Responses
were grouped into five categories: ‘cyclist non-compliance with previous
traffic control’, ‘presence of a contra-flow bicycle movement’, ‘a diagonal (or
otherwise unique) cyclist path through the intersection’, ‘safety concerns for
cyclists’, and ‘other’. The survey responses indicated that bicycle signals are
most commonly installed when cyclists are moving against motor vehicle
movements, taking a non-standard path through an intersection, or when there
are safety concerns for cyclists at that intersection. Many signals in
Vancouver, BC and Montreal, QC are used to control contra-flow movements on
two-way cycle tracks.
Bicycle-specific traffic signals are common in many places
throughout Europe, however, they are a new tool for transportation engineers in
North America. The availability of engineering guidance has improved
substantially over the past few years with the release of the California MUTCD,
NACTO’s Urban Bikeway Design Guide,
and AASHTO’s guidance. While there are minor differences, there is generally
consistent guidance. To some extent, the guidance documents reflect the lessons
learned by the surveyed jurisdictions since installation of the bicycle-specific
signals is limited to those places willing to experiment. The survey of
practice found a variety in some design elements: lens size, use of insignia,
utilization of louvers, mounting location, and the means to designate that the
signal head is for bicyclists. Some consensus appears on the use of the lens
insignia and accompanying signage. Given the accelerated deployments of
bicycle-specific signals and the new guidance documents, it is likely that
there will be less variety in future designs. Adoption of minimum guidance in
the U.S. MUTCD would also likely improve consistency and practice. The National
Committee on Uniform Traffic Control Devices is presently considering language
addressing bicycle-specific signals.
Thompson, S. Monsere, C. Figliozzi,
M., Koonce, P. Obery,
G. “Bicycle-Specific Traffic Signals: Results from State-of-the-Practice
Review” Transportation
Research Record: Journal of the Transportation Research Board, No. X, Transportation Research Board of the
National Academies, Washington, D.C., 2013. InPress. Link:
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