ITE Journal May 2018 - 38

Pedestrian Priority
Many signal controllers provide users with the ability to incorporate
custom logic commands, which allow for greater flexibility in
operation. These logic commands can be successfully leveraged to
build simple algorithms that provide the user with the flexibility to
change modal priorities at the intersection based on real time inputs.
Sobie et al. describe the development and implementation of
a pedestrian priority algorithm using the logic processor on an
ASC/3 controller. The traffic responsive algorithm is designed
to change the operational plan of a traffic signal to a plan that is
favorable to pedestrians when vehicular volumes drop below a
certain threshold.13 Their findings revealed that the algorithm was
successful in reducing minor-street pedestrian delays.
This algorithm can be implemented at any intersection with a
signal controller that has logic command capability. Although this
work was constructed on Econolite's ASC/3 platform, it could easily
be adapted to other signal controller platforms, or implemented
on a PLC or Raspberry Pi type device. The algorithm in its current
form is best suited for coordinated intersections, with higher majorstreet and lower minor-street volumes.

The Barnes Dance is best suited at locations where very high
pedestrian or right turning volumes create the need to completely
separate modes. An LPI is best suited for locations where geometry
and/or vehicle volumes cause issues for pedestrians entering the
crosswalk. Short cycle lengths provide the practitioner with the
option of operating in coordinated mode while trading green
bandwidth for reduced delays for minor-street phases. Free
operation is the most aggressive strategy resulting in lower delays
for most users at the expense of major-street traffic. Actuated
coordinated operation can provide lower pedestrian delays for
the minor-street phases, if the major-street phases gap out and
is useful for low-moderate pedestrian volumes. The pedestrian
priority algorithm bridges the gap between conflicting objectives by
allowing the controller to prioritize service to different users based
upon vehicle inputs. Figure 4 shows a graphic with recommendation on when and what type of pedestrian strategies to implement
based on v/c ratios and pedestrian pushbutton actuation frequency,
which is the percent of cycles that have pedestrian calls.

Ranking of Control Strategies
Table 1 shows the ranking of the control strategies based on majorstreet vehicular delays and minor-street pedestrian delays based
on research by Kothuri et al.4 Higher numbers indicate increased
delays. For pedestrians, free operation resulted in lowest delay and
Barnes Dance produced the highest delay. For vehicles, coordination
produced the lowest delay for the major-street phases and Barnes
Dance resulted in the highest delay. Of course, while changes in the
settings of the various strategies could adjust the order presented
below, these rankings provide a general comparative list of the
various strategies. Please note that pedestrian priority is not listed in
this table because it can be employed with any of the listed strategies.
Table 1. Ranking of Control Strategies
Control Strategy
Free operation
Short cycle lengths
Leading pedestrian intervals
Actuated coordination
Coordination
Barnes dance

Figure 4. Recommendation on Implementation of Pedestrian-focused Strategies
Pedestrian
Delay Ranking
1
2
3
4
5
6

Vehicle Delay
Ranking
4
3
5
2
1
6

Note: 1 is least amount of delay and 6 is the most, all other things being equal.

Recommendations
While the choice of a control strategy depends on operational
objectives and intersection characteristics, a few general recommendations related to the deployment of specific strategies are provided here.
38

May 2018

i te jo urn al

Conclusions
Traditional signal timing practices often prioritize vehicular
movements at signalized intersections over other system users.
However, an increase in non-motorized modes especially in urban
areas had led to greater consideration of the actual operating
environment and incorporates the needs of all users. In this article, a
number of pedestrian focused signal control strategies were presented
along with expected impacts and recommendations on what might
meet the needs based on activity and context. Generally, there is no
one solution for all situations. Implementation of a control strategy
depends upon operational objectives and intersection characteristics. Ultimately, tradeoffs in delays between user groups should be
addressed to prioritize different modes based upon time of day. itej



Table of Contents for the Digital Edition of ITE Journal May 2018

President’s Message
Director’s Message
People in the Profession
ITE News
ITE, FHWA, and Carmanah Rally to Keep Rectangular Rapid-Flashing Beacons in Our Safety Toolbox
Improving Arterial Roads to Support Public Health: How Can We Do This?
ITE’s Transportation and Health Initiative
Technical Programs Division Spotlight
Industry News
Calendar
Where in the World?
Member to Member: Jing Zhang, AICP, PTP, LEED AP ND
Countermeasures Prove Effective in Reducing Bicycle Collisions
Guidance on Signal Control Strategies for Pedestrians to Improve Walkability
Factors Affecting Vehicle Passing Distance and Encroachments While Overtaking Cyclists
Measuring the Success of Modal Shift: The Impact on Last Mile Connectivity
Professional Services Directory
ITE Journal May 2018 - 1
ITE Journal May 2018 - 2
ITE Journal May 2018 - 3
ITE Journal May 2018 - President’s Message
ITE Journal May 2018 - 5
ITE Journal May 2018 - Director’s Message
ITE Journal May 2018 - 7
ITE Journal May 2018 - People in the Profession
ITE Journal May 2018 - 9
ITE Journal May 2018 - 10
ITE Journal May 2018 - ITE News
ITE Journal May 2018 - ITE, FHWA, and Carmanah Rally to Keep Rectangular Rapid-Flashing Beacons in Our Safety Toolbox
ITE Journal May 2018 - Improving Arterial Roads to Support Public Health: How Can We Do This?
ITE Journal May 2018 - 14
ITE Journal May 2018 - 15
ITE Journal May 2018 - 16
ITE Journal May 2018 - ITE’s Transportation and Health Initiative
ITE Journal May 2018 - 18
ITE Journal May 2018 - Technical Programs Division Spotlight
ITE Journal May 2018 - Industry News
ITE Journal May 2018 - 21
ITE Journal May 2018 - Where in the World?
ITE Journal May 2018 - 23
ITE Journal May 2018 - 24
ITE Journal May 2018 - 25
ITE Journal May 2018 - 26
ITE Journal May 2018 - Member to Member: Jing Zhang, AICP, PTP, LEED AP ND
ITE Journal May 2018 - 28
ITE Journal May 2018 - Countermeasures Prove Effective in Reducing Bicycle Collisions
ITE Journal May 2018 - 30
ITE Journal May 2018 - 31
ITE Journal May 2018 - 32
ITE Journal May 2018 - 33
ITE Journal May 2018 - 34
ITE Journal May 2018 - Guidance on Signal Control Strategies for Pedestrians to Improve Walkability
ITE Journal May 2018 - 36
ITE Journal May 2018 - 37
ITE Journal May 2018 - 38
ITE Journal May 2018 - 39
ITE Journal May 2018 - Factors Affecting Vehicle Passing Distance and Encroachments While Overtaking Cyclists
ITE Journal May 2018 - 41
ITE Journal May 2018 - 42
ITE Journal May 2018 - 43
ITE Journal May 2018 - 44
ITE Journal May 2018 - 45
ITE Journal May 2018 - Measuring the Success of Modal Shift: The Impact on Last Mile Connectivity
ITE Journal May 2018 - 47
ITE Journal May 2018 - 48
ITE Journal May 2018 - 49
ITE Journal May 2018 - Professional Services Directory
ITE Journal May 2018 - 51
ITE Journal May 2018 - 52
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