ITE Journal - July 2020 - 45

such as the number of bicycle faces, mounting heights, distance
from the stop line, use of arrows, lens diameter, use of colored
housing or backplates, presence of visibility restricted louvers,
and other data elements. The history option in Google Street
View (when available) or agency data, the year of installation was
determined for 80 percent of the inventory.
As would be expected, the inventory documented an
increasing number of installations of bicycle signals after IA-16
was issued in 2013. The states with the most intersections with
bicycle signals were New York (156), California (70), Illinois (40),
Washington (51), Oregon (33), and Texas (26), with large cities
in these states being the primary adopters. The map in Figure 2
shows the location of intersections. Table 1 highlights the cities
with 10 or more intersections in the inventory.***
Detailed signal timing was challenging to obtain. Instead, the
research team assessed the primary purpose of using the signal
control for bicycles by inspection of the geometry and placement
of the signals. A partial summary of this assessment is presented
in Table 2. Many of the intersections in the inventory are part
of a corridor, where signal control and design are replicated at
multiple intersections. As a result, frequency summaries partially
reflect repeated designs. The most common bicycle signal uses are
to facilitate the contra-flow movement of a two-way bicycle lane
and to provide separation when the bicycle lane is placed left of a
left-turn lane or right of a right-turn lane. Other typical use cases
include controlling bicycle movements at connections to two-way
facilities or paths, controlling contra-flow and diagonal bicycle
movements, left turns, and crossings for multiuse paths. In many
of these applications, the bicycle signal face was not visible to
drivers in motor vehicles.
Table 3 summarizes the number of signal heads, lens
diameter, and visibility distance per approach. Visibility distance
from the stop line to the signal face was measured using Google
Maps. Though IA-16 only requires a second signal face for
intersections when the primary signal face is more than 120 feet
(ft.) (36.6 meters [m]) from the stop line and suggests a second
signal face for more than 80 ft. (24.4 m), many installations used
two signal heads for bicycles even when the distances to the stop
bar were less than 120 ft. Two-thirds of the lenses with the bicycle
symbol in the inventory were 8 inches. The selection of lens size
did not have an apparent relationship with visibility distance.
IA-16 also allows optional use of a 4-inch nearside signal. There
were only a few locations identified with 4-inch heads (mostly
in Portland, OR as the research team had direct knowledge of
these locations) because the data collection approach made it
difficult to identify these smaller signal heads optimally placed
for viewing by persons on a bicycle.
***	 At the time of the inventory the research team was aware of signal faces in Hawaii (mostly along South King
Street in Honolulu) but was unable to obtain further details.

Table 4 presents the summary of the horizontal and vertical
distance between the far-side primary bicycle signal face and
the nearest vehicular signal face, rounded to the nearest foot.
The horizontal offset was measured between the edge (either
the signal housing or the backplate) of the bicycle signal face
to the nearest motor vehicle signal face. No protocol for the
vertical separation measurement was found, so the distance
was measured from the top edge of the bicycle signal face to the
bottom edge of the motor vehicle signal. IA-16 suggests that a
bicycle signal face be separated vertically or horizontally from the
nearest motor vehicle traffic signal face for the same approach by
at least 3 ft. (0.9 m). Most of the signal faces in the inventory met
the horizontal and vertical separation from vehicular signal heads
recommended in IA-16.
To make the inventory available to practitioners and
researchers in an easy-to-use format, the research team posted
the data collected from the project, including the map of signals
online.8 Data for each intersection are posted in a sheet format
and include most of the categories described in this section. The
map interface includes direct links to the Streetview image of the
bicycle signal face. The site includes a link to report new signal
faces and the map includes locations identified after the end of
the project.

Figure 2. Map of Intersections with Bicycle Signal Faces.
Table 1. Jurisdictions with Ten or More Intersections with Bicycle
Signal Faces
City
Atlanta, GA

Number of
City
Intersections
17
Long Beach, CA

Number of
Intersections
18

Austin, TX

16

Los Angeles, CA

17

Boston, MA

12

Minneapolis/St. Paul, MN 14

Chicago, IL

32

New York City, NY

154

Denver, CO

14

Portland, OR

25

Houston, TX 10

San Francisco, CA

24

Lincoln, NE

Seattle, WA

51

10

w w w .i t e.or g

J u ly 2020

45


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ITE Journal - July 2020

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