TRAININGPTV Vistro
Advanced Traffic Signal Training

Karlsruhe, 2023

Top

Contents
1

Starting out ............................................................................................................................................ 4
1.1

Global Settings .............................................................................................................................. 4

1.1.1
1.2

Default Signal Group scheme ............................................................................................... 4

User Interface for Traffic Signal Controllers .................................................................................. 7

1.2.1

Placing a signal refresher ...................................................................................................... 7

1.2.2

Network Graphic Parameters for Traffic Signal Parameters and Analysis ........................... 8

1.2.3

Signal Control Menu .............................................................................................................. 8

1.2.4

Traffic Signal Workflow Table ............................................................................................... 9

1.2.5

Multi-Change Tool ............................................................................................................... 12

2

Traffic signal controller setup .............................................................................................................. 12

3

Steps in creating signal controllers and performing local optimization ............................................... 20
3.1

Default Signalization ................................................................................................................... 20

3.1.1
3.2

Manual Signalization setups ....................................................................................................... 24

3.2.1

Assigning signal groups ...................................................................................................... 25

3.2.2

Signal Groups Window ........................................................................................................ 25

3.2.3

Phase diagram .................................................................................................................... 25

3.3

4

Pedestrian Clearance (Flashing Don’t Walk) Estimation .................................................... 22

Advanced Settings ...................................................................................................................... 27

3.3.1

2 or More Intersections on 1 Traffic Signal Controller......................................................... 27

3.3.2

Pedestrian fixed-time, recall, and push-button settings ...................................................... 28

3.3.3

Exclusive Pedestrian Phase................................................................................................ 30

3.3.4

Delayed Vehicle Green ....................................................................................................... 31

3.3.5

Overlaps .............................................................................................................................. 34

3.3.6

Montreal’s Leading Thru Configuration with Overlaps ........................................................ 34

3.4

Local and Automatic Optimization............................................................................................... 35

3.5

Renumbering Controller IDs........................................................................................................ 36

Network Optimization .......................................................................................................................... 37
4.1

Coordination Groups ................................................................................................................... 37

4.1.1

Create a Coordination Group .............................................................................................. 38

4.1.2

Assign Coordination Group ................................................................................................. 38

4.1.3

Selecting a Master Controller .............................................................................................. 39

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5

4.2

Network Optimization Settings and Running .............................................................................. 40

4.3

Routing ........................................................................................................................................ 43

4.4

Network Optimization Workflow and Time-Space Diagrams ...................................................... 44

Additional Special Cases .................................................................................................................... 46
5.1

6Transit or Bicycle Active TSP ...................................................................................................... 47

Migration from Synchro ....................................................................................................................... 47
6.1

Global Settings ............................................................................................................................ 47

6.2

Importing a Combined .csv ......................................................................................................... 48

6.3

Merge .......................................................................................................................................... 48

6.4

Update ......................................................................................................................................... 48

TablesTable 1-1: NCHRP Report 812's NEMA Phasing Scheme ........................................................................... 4
Table 1-2: Global Setting Parameters for setting up a traffic signal using HCM Methods ........................... 5
Table 1-3: Network Graphic Parameters useful for Traffic Signal Controller Setup and Analysis ................ 8
Table 1-4: Signal Control Menu .................................................................................................................... 9
Table 2-1: Typical traffic signal controller setup terminology ...................................................................... 13
Table 2-2: Typical traffic signal controller results terminology .................................................................... 19
Table 4-1: Network Optimization Settings and Description ........................................................................ 41

ExamplesExample 3-1: Understanding Pedestrian Clearance Calculations .............................................................. 23
Example 3-2: Create a Passive Transit Signal Priority Signal Group (Hold Phase) ................................... 26
Example 3-3: Pedestrian Push button and Recall Settings ........................................................................ 29
Example 3-4: Create and LPI with Delayed Vehicle Green ........................................................................ 32
Example 3-5: Creating Montreal’s Leading Thru Configuration with Overlaps and Delayed Vehicle Green.................................................................................................................................................................... 34
Example 4-1: Creating and Assigning a Coordination Group, and selecting a Master Controller .............. 39

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1 Starting out
1.1 Global Settings
When starting a new project it is best to revisit Global Settings at Edit->Global Settings to ensure that the signal parameters are set to youragency preferences. Each signal created (or converted signal not containing the specified data) will have these global defaults.
Note: Global Settings can be changed at any time during the project to adapt to multiple locations or corridors, districts, or jurisdictions with aproject.
Additionally, Default Signalization utilizes the Global Setting parameters when automatically setting up the traffic signal controller. See Page
20 for Default Signalization information.
For the full list of Global Setting Parameters for setting up a traffic signal using HCM Methods, see Table 1-2 on Page 5. A few additionalparameters are available if the Canadian Capacity Guide methodology is selected as an analysis method.
Tip: Global Settings should be reviewed and adjusted as needed before Importing a in a Synchro model, as Vistro most often includes more
information than Synchro. See Section 0 for more information on Synchro .csv Imports or model Merging and Updates.
Back to top

1.1.1

Default Signal Group scheme

Excerpted from Table 1-2, intersections created with default signalization will use the following NEMA signal group orientation defaults forthe major and minor flow directions, or any other agency signal group scheme. By default, Vistro follows the NEMA scheme, as shown in
Figure 1-1 from NCHRP Report 812, Signal Timing Manual, Second Edition’s Exhibits 5-1 and 5-3.

Table 1-1: NCHRP Report 812's NEMA Phasing Scheme
Signal Group Scheme Parameter
Major Flow Direction

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Description
Determines if the north-south direction or the eastwest directions should be the set to the major flow.

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Northbound Signal Group (major)

North-westbound Signal Group (major)

North-eastbound Signal Group (major)

Eastbound Signal Group (major)

If the north-south directions are the intersection’s
major flow, this determines the default northboundsignal group.
Determines the default major flow signal group for
skewed intersections in the north-westbounddirection.
Determines the default major flow signal group for
skewed intersections in the north-eastbounddirection.
If the east-west directions are the intersection’s major
flow, this determines the default eastbound signalgroup.

Figure 1-1: NEMA Traffic Signal Phasing

Table 1-2: Global Setting Parameters for setting up a traffic signal using HCM Methods
Global Setting Parameter
Analysis Period
Located in CBD

 PTV GmbH Feb-23

Default Setting
15 minYes

Optional Setting
1 hr
NoPage 5/48

Traffic Control Workflow
Intersection Settings
Intersection Settings

Major Flow Direction
Northbound Signal Group (major)
Northwestbound Signal Group(major)Northeastbound Signal Group(major)Eastbound Signal Group (major)
Lead/Lag Setting
Cycle Length (s)Coordination Type
Actuation Type
Offset Reference

North-South6
6

East-West2, 4, 82, 4, 8Intersection Settings
Phasing & Timing
Phasing & Timing

2

4, 6, 8

Phasing & Timing

2
Lead
90
Time of Day Pattern Coordinated
Fixed Time
LeadGreen – Beginning of First
Green4, 6, 8Lag
0-255Time of Day Pattern Isolated, Free Running
Fully Actuated, Semi-ActuatedPhasing & Timing
Phasing & Timing
Intersection Settings
Intersection Settings
Intersection Settings Beginning of Both Green; Intersection Settings Beginning of First Yellow;
 Beginning of First Red;
 Beginning of First Flashing Don’t
Walk; LagFO; LagEnd; CoordEnd;
Permissive Mode
Intersection Lost Time (s)Minimum Green, Through (s)Minimum Green, Left (s)Amber (s)Allred (s)Vehicle Extension (s)Walk (s)Pedestrian Walking Speed (ft/s)

Single Band
0
10
5
3.0
1.0
3.0
5.0
3.50 f/s (1.07 m/s)

Multi-Band, Reservice
0-(cycle length-0.1) s0-255 s0-255 s0-255 s0-255 s0-25.5 s
0-255 sBack to top

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Intersection Settings
Intersection Settings
Phasing & Timing
Phasing & Timing
Phasing & Timing
Phasing & Timing
Phasing & Timing
Phasing & Timing
Intersection Settings

2 User Interface for Traffic Signal Controllers
2.1.1

Placing a signal refresher

Junction Type: To place a signalized using the junction type, select the signalized intersection junction
type from the expansion list. Then, with the intersection placement icon displayed, left-click on thebase map to place the junction at the desired location.

->

Right-Click: A signalized intersection can be placed at the mouse position by using the Right-Clickbutton on a roadway segment’s Leg or on at a location on the base map. The right-click will open thecontext menu. Then select Insert Intersection -> Signalized.

Copy and Paste: A signalized intersection can be placed by copying and pasting an existing signalizedintersection. This will make an exact copy of the signal; however, the location will be assigned a new
Intersection Number and Controller ID. This can be achieved by selecting an intersection, right-clicking
to open the context menu, and selecting Copy Intersection. To paste an intersection, find a desired
location on the base map, right-click to open the context menu, then select Paste Intersection.
CTRL+C and CTRL+V are intersection copy and paste shortcuts, respectively.

->

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Back to top

2.1.2

Network Graphic Parameters for Traffic Signal Parameters and Analysis

PTV Vistro includes many graphic parameters that are useful for traffic signal controller setup andevaluation, as shown in Table 1-3. For example, showing signal groups in the network editor enables
you to see exactly what movement is allocated which signal group number at the intersection creatingstrong correlations to the Phasing & Timing Tables, Phase Diagram, and Sequence.

Table 1-1: Network Graphic Parameters useful for Traffic Signal Controller Setup and Analysis
Graphic Parameter

Toolbar Icon

Description

Show Signal Groups

Shows the signal groups per approach
movement as indicated in the Traffic Control
Workflow, sequence, and phase diagram.

Show Detailed Traffic
ConditionsShow movement and lane group results oneach approach per the Traffic Control
Workflow calculationsShow Intersection
Info

Shows intersection information. Regarding
traffic signals, the controller type, controller,
number, coordination group, cycle length,
and intersection ICA check displays useful
information.

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2.1.3

Signal Control Menu

Next, the Signal Control menu, summarized in Table 1-4, contains the tools and lists for traffic signal
setup, optimization, and editing.

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Table 1-2: Signal Control Menu
Menu Items

Control Window

Description

Default
Signalization

Creates default signalization for ALL
intersections at 1 time.

Network
Optimization

Contains settings for network optimization
along 1 or multiple coordination groups.

Local
Optimization

Contains settings for local optimization andthe option to optimize all intersections at
one time locally.

Edit
Controllers

Enables renumbering of Controller ID
numbers and add controller descriptions orinventory information. This lists theassociated Intersection(s) number to eachController ID. Lists can be filtered.

Edit
Coordination
GroupsCreate, delete, and name coordinationgroups. Also, a Master Controller ID can beselected from a list of intersections that are
members of each coordination group.

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2.1.4

Traffic Signal Workflow Table

Traffic signal information is entered on the Traffic Control Workflow table. The Control Type needs tobe set to Signalized to create and edit a traffic signal controller.

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Figure 1-1: Traffic Signal Workflow TableOn this workflow table, there is a special toolbar that is useful for traffic signal optimization, calculation
checking, and data entry.

Figure 1-2: Traffic Signal Workflow Toolbar

Menu Items

Description

ICA Check

This tool checks for basic parameters used for an Intersection Capacity
Analysis. This tool along with the graphic parameter (Show Intersection
Info -> ICA check) provides a basic quality control check of the model.
Clicking on this button displays warnings or critical error messages
useful to fix the intersection’s setup.

Automatic
Optimization

Default Signalization

 PTV GmbH Feb-23

When checked, Automatic Optimization can be used to quickly optimize
intersection, locally. This is useful when new volume parameters,intersection configurations, trip distributions, assignment information,and other relevant parameters are entered. Default Optimization
parameters will be taken from Global Setting and the Local Optimization
settings under the menu Signal Control->Local Optimization.
After setting the primary controls and methods, this button activates
default signalization at the active intersection. This generates signalgroups based on the control types and the Sequence and Phase
Diagram for common 3 and 4-leg intersections. Default Signalization will
use the timing parameters defined in Global Settings and the Major andMinor street Priority Scheme to allocate the NEMA phasing convention.
Min. green times and clearance intervals will be overwritten.

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Optimize Split andCycle Time

This button activates the Local Split and Cycle Time optimization menu,
but only for the active intersection. Intersection min. green times andclearance intervals are respected. Here local settings and optimization
strategies can be selected, such as upper and lower limits to the cycle
length, step sizes, objective functions.

Optimize Split

This button activates the Local Split (only) menu, but only for the active
intersection. Intersection minimums and clearance intervals arerespected. Here local settings and optimization strategies can beselected, such as upper and lower limits to the cycle length, step sizes,
objective functions.

Signal Groups Menu

Search Bar

 PTV GmbH Feb-23

This button opens a window that lists active or inactive signal groups
defined to the controller. In use or not, these signal groups can be
assigned to the sequence, to movements, or auxiliary signal groups usedin overlaps. This window should be used for advanced intersections,such as multiple intersections set to 1 controller, intersections with “holdphases” for transit signal groups, or in the case of tight diamond
overlaps. This window will display the signal groups in numerical orderfor easy editing and reference enable you to enter overlaps to use as a
special Auxilary Signal Group not already assigned to a movement.

Within each workflow, a search term can be entered to filter the current
Workflow Table. This can be useful to quickly find key parameters,
calculation values, or results by name, partial text string, or keyword(s).

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Workflow Pop-out

Some locations require more monitor space to view numerous
movements and information. This button enables multi-monitor layouts
with a full-screen experience by popping out the workflow tables. Use
the windows maximize button to dock the workflow display.

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2.1.5

Multi-Change Tool

After intersections are created in Vistro, it may be necessary to update a single, a few, or all
intersection parameters all at 1 time, such as clearance intervals, minimum green times, analysis
methods, or right-turn on red methods. The multi-change tool can be used to update key attributes
all at once or by customizable selection sets using the list sorting and filtering functionality.
Additionally, intersections can be viewed by coordination groups to select intersection sets by acorridor or district. The following is an overview of the multi-change tool.
1. Under the Edit Menu, select Multi Change.
2. Select the Attribute to change.

3. Enter attribute value to apply to the intersection selection set
4. Selection Filters:•••

All intersections or No intersections using the quick icons.
Sort ascending or descending by left-clicking on the column headers
Filter list by hovering over a column header and left-click the funnel .

Back to top

 PTV GmbH Feb-23

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3 Traffic signal controller setup
The following is a list of PTV Vistro’s traffic signal controller inputs, along with a description, guidanceon using the parameter, and the Synchro Equivalent parameter, if applicable. For more detailed
descriptions and units of each parameter, visit the Vistro help under Chapter 8.

Table 2-1: Typical traffic signal controller setup terminology
Parameter
Intersection Settings
Priority Scheme

Analyze Intersection?
Analysis Period
Located in CBD
Controller ID

Signal Coordination
Group
Cycle Length

Coordination Type

Actuation TypeShort Description

SynchroEquivalent

Sets which approaches are the major or minor streets. This is
set with Global Defaults; however, can be modified at any
time.
This indicates this intersection will be included in the reports.
The time period for the analysis
A check box indicates the intersection is in a central business
district. HCM for a description of the CBD area.
Each signal controller has a unique ID number. This valuedefaults to the intersection number, or intersections canshare a controller.
To edit default Controllers IDs to another number or
specialized agency number systems open the Edit
Controller window under Signal Controller ->Edit
Controllers.

-Signalized intersections of the same subgroup arecoordinated collectively. Multiple subgroups (coordinatedroutes) are permitted.
Controller cycle length. This is the maximum time it will takefor each signal group to cycle once. The cycle length is onlyused for coordination.
Defines coordination as Free, Time of Day Pattern
Coordinated, or Time of Day Pattern Isolated.

Zone

The following describes coordination methods:•
Free-running means that the traffic signal controller
does not have a set cycle length and is running withfully actuated detection.
•
Time-of-day Coordinated sets a cycle length andplaces the controller in coordination with othersignals in the same coordination group.
•
Time-of-day isolated sets a cycle length but does
not place the controller in coordination with othersignals.
Defines whether the controller operates as:

Analysis Time Period
Area Type CBD
Node#Cycle Length

Control Type

Control Type Fixed-time(pre-time)
controlconsistsofpredetermined signal timing values not based on thedetection.

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 Fully actuated: If the Coordination Type is not Free
Running, the fixed time signal plan is used to calculate
the Force-Off Points of the non-coordinated phases.
The user has to provide a valid and useful fixed time
signal plan. By modifying the signal plan, the user can
influence the calculated Force-Off Points withmaximum and minimum green inputs, recalls, andvehicle extensions. This control type sets detection on
all lanes that influence signal operations.

 Semi-actuated: contains some lanes with detectionthat influences signal operations. Often, the majorstreet thru lanes do not operate with detection to
generate phase calls.
OffsetOffset Reference

 PTV GmbH Feb-23

When coordinated, the local cycle timer will be offset fromthe master cycle timer by the defined offset time relative tothe reference point.

OffsetThis is the point in the cycle where the master cycle
timer will be equal to the defined Offset time when thecontroller is coordinated and not in transition (offset
seeking). Further explanations can be found in NCHRP
Report 812 – Signal Timing Manual. The selections are:

Reference to•

Lead Green – Beginning of First Green: The
reference point will be at the start of the leading
coordinated signal group green (the computed startof green, note that the signal group may return togreen early if there is a lack of demand on opposing
movements).

•

Beginning of Both Green – at start of 2nd coordinatedgreen (both are green)•

Beginning of First Yellow – start at first coordinatedyellow•

Beginning of First Red – start at first coordinated red•

Beginning of First Flashing Don’t Walk•

LagFO (Lagging Force-Off) – The reference point will
be at the force-off point for the lagging coordinatedsignal group.

•

LagEnd (End of Lagging Red) – The reference point
will be at the end of Red Clear for the lagging
coordinated signal group.

•

CoordEnd (End of Coordinated Group Red) – Thereference point will be at the end of red for the last
signal group in the concurrent barrier group with thecoordinated signal groups.

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Permissive Mode

This setting defines the permissive mode for thecoordination pattern per NCHRP Report 812 – Signal
Timing Manual.

Yield Point

The permissive mode controls the method in which
permissive periods are opened and closed for all noncoordinated signal groups. The controller will only
yield to signal groups that are permissive following theend of green on each coordinated signal group. The
permissive modes are as follows:•

Single- and multi-band modes: The singleband permissive mode starts all permissive
signal groups at the same time (one band).
The multi-band permissive mode starts one ata time, where the next permissive band opens
after the last one closes (multiple bands).

The advantage of single-band permissive mode is that,
under light traffic volumes, there is the ability to skip
minor street (or non-coordinated phases 4 & 8 in theimage) and call perhaps the main street turning
phases early (phases 1 and 5 in the example image) if
the Phase 1 call comes before Phase 4. This is better if
the main street is Agency the priority and the minor
street is not a high priority. For “fairer” operations on
the minor street, multi-band allows for an opportunity
for a side street to be reevaluated and is not a first PTV GmbH Feb-23

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come-first-serve detection after the yield point
between 1/5 and 4/8. If detection of 4/8 comes along
after a call on 1/5, 4/8 goes first still (if there is still time
for the call to be considered and not skipped).

•

Lost Time

Phasing & Timing
Control Type

Total intersection time per cycle that is not effectively
being used due to driver reaction time, acceleration,and deceleration at the start and end of active signalgroups. This is typically three to four seconds per
signal group, times the number of signal groups.
Defines control of movements as permissive; protected;
protected / permissive; split; overlap; unsignalized (outerturns only using HCM 6th Edition) Control Type for eachmovement should be reviewed under the Phasing & Timing
section and set to the following:••• PTV GmbH Feb-23

Reservice: The permissive mode will operate
the same as Single Band Permissive until thecoordinated signal groups yield to a noncoordinated movement. ALL signal groups willbe allowed to reserve. After the coordinatedsignal groups yield once.
-

Turn Type

Permissive (Permitted) control requires motorists tochoose acceptable gaps and/or yield to conflicting
vehicles or pedestrian traffic streams.
Protected control assigns the right-of-way toturning drivers.
Protected/permissive control has a protectedsignal group assigning right-of-way to turning
drivers that then transitions to the permissive parent
signal group, requiring turning vehicles to yield.
Permissive/protected control is modeled by
selecting protected/permissive and changing the
Lead/Lag setting to Lag.

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Note: In the HCM there are special requirements to ensure
safe operations for Shared Thru/Left protected/permissive
operations. Shared thru/left are set to recall per the HCM.
Max green for the left turn is equal to the min green of thethru since the left and thru are shared. Vistro will fix thesesettings if implemented differently to meet theserequirements.
•

Split phasing control provides separation between
signal groups within the same barrier and prohibits
the signal groups from running concurrently.

•

Allow Lead/Lag
Optimization
Signal Group
Auxiliary Signal Groups

Lead/Lag
Minimum Green

Maximum GreenAmber
All red
Split

Vehicle Extension

Walk PTV GmbH Feb-23

Overlap control is a controller output thatcombines two or more non-conflicting signalgroups. This is mostly used to combine signalgroups that sit in separate barriers. A common
example is when a right-turn movement has anoverlap phase running concurrently with the“shadowing” left-turn movement on the cross-street.
Note: Overlaps can be set for all movements to create
advanced signal group combinations like those seen in tightdiamond interchanges.
Checkbox to allow for lead/lag optimization.
The signal group is the signal phase number.
All signal groups serving the movement. When the Control
Type is “Overlap” and the Signal Group for the Overlap
phase is entered, the Auxiliary Signal Groups cell is active
and allows selections of any phases with which thismovement overlaps.
Selection for Lead or Lag left turn for protected phasing.
The minimum green time that the signal group will serve
before changing to yellow. Note: Min Green value needs tobe updated manually when the optimized split isdetermined. Different default Minimum Greens can be set
for left and through movements in the Global Settings.
The maximum time that the signal group will be allowed toextend before it will max-out. A max-out will make a signalgroup eligible to terminate, even though it may not havegapped-out. This parameter when exported to RBC isreflected as Max1.
Time a signal group will time an amber interval before
advancing to red.
Time a signal group will time red before a conflicting signalgroup will be allowed to begin timing.
Amount of time allocated in the cycle for each signal group
to time. The split includes the time it will take the green,
yellow, and red intervals to time for each signal group.
Allowed time between successful vehicle extensions before
a signal group will gap out. This parameter may be referred
to as passage in some controllers.
The minimum time a signal group will display a walkindication before advancing to the pedestrian clearance

Allow Lead/Lag
Optimize
X_Y phase setup
convention in
SynchroLagging Phase?
Minimum Initial-

Yellow Time
All-Red Time
Total Split

Vehicle Extension

Walk Time

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Pedestrian Clearance

Delayed Vehicle Greenl1, Start-Up Lost Timel2, Clearance Lost Time
Coordinated
Minimum Recall

Maximum Recall

Pedestrian Recall(Pedestrian pushbutton)

Dual Entry

Detector
Detector Location
Detector Length PTV GmbH Feb-23

interval (flashing don’t walk). A signal group may notadvance to yellow while the pedestrian movement is in the
walk interval.
Time a signal group will display a flashing don’t walkindication before advancing to solid don’t walk. A signalgroup may not advance to Yellow while the pedestrian
movement is in the pedestrian clearance interval. Pedestrian
clearance is estimated based on lane widths and medianwidths when Default Signalization is clicked. Note: This is an
estimated crossing time and engineering judgment should
be used to calculate field-based pedestrian clearanceintervals.
Used to establish Lead Pedestrian Intervals. This value is theamount of time that the vehicle green interval is delayed
before the start of vehicle Green allowing the pedestrian
walk interval to start first.
Additional time needed to react to the initiation of the green
signal and then accelerate.
The time between signal indication changes during which
the intersection is not used by vehicles.
Identifies the coordinate signal groups for the signal
controller.
Signal groups flagged for this option will receive an
automatic vehicle call regardless of actuation and time for atleast its minimum green time. The green time may extend
beyond the minimum if demand is present.
Signal groups flagged for this option will receive an
automatic vehicle call and extension. The maximum green
timer will unconditionally begin timing at the beginning ofgreen. Normally, the maximum green timer will only time ifthere are opposing calls to the signal group.
Signal groups flagged for this option will receive an
automatic pedestrian call and time for the full walk plus
pedestrian clearance time.
NOTE: This box does not need to be checked with fixed time
signals to recall pedestrians, as this is automaticallyassumed. For non-fixed time signals, if this box is notchecked and crosswalks are present, Vistro will automaticallyassume that this intersection has a pedestrian push button orpedestrian detector to activate a pedestrian call.
When a signal group has a call in the next barrier group,
concurrent phases in that barrier group may not have a call.
In such cases, both the signal group with the call and thesignal group with no call will begin timing when the barrier iscrossed if both signal groups are flagged with Dual Entry.
This feature is often used for through movement signalgroups such that if one signal group is called, the signalgroup in the opposite direction will automatically serve, even
if it does not have a call.
Checkbox to choose detector for the Signal GroupDistance upstream of stop bar of the leading edge of thedetector.
Length of the detector.

Flashing Don’t Walk-

Recall Mode
Recall Mode

Recall Mode

Recall Mode

Dual Entry

Detector Phase
Detector 1 Position
Detector 1 Size

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I, Upstream Filtering
FactorAdjustment factor to account for the effect of an upstream
signal on vehicle arrivals to the subject movement group.
This is currently user-defined.
Exclusive Pedestrian Phase
Pedestrian Signal
The signal phase number for the exclusive pedestrian phase.
Group
All other pedestrian signal groups on each approach will belocked. This pedestrian signal group must be added to thesequence.
Pedestrian Walk
The minimum time the exclusive pedestrian signal group will
display a walk indication before advancing to the pedestrian
clearance interval (flashing don’t walk). A signal group may
not advance to yellow while the pedestrian movement is in
the walk interval.
Pedestrian Clearance
Time the exclusive pedestrian signal group will display aflashing don’t walk indication before advancing to solid don’t
walk. A signal group may not advance to Yellow while thepedestrian movement is in the pedestrian clearance interval.
Arrival TypeThe arrival type selects the Platoon Ratio which describes thelevel of platooning quality arriving at the selected approach.
The platoon ratio will be automatically updated based on theselection of Arrival Type per approach.
Default = 3; Range = 1 – 6 (very poor – exceptional
coordination)
1 Very Poor Progression
2 Unfavorable Progression
3 Random Arrivals or Uncoordinated (default)
4 Favorable Progression
5 Highly Favorable Progression
6 Exceptionally Favorable Progression

HCM Upstream
Filtering Factor

Ped Hold

Walk Time

Flashing Don’t Walk-

The Arrival Type should be updated to match the field ordesired conditions. See the HCM for further guidance on theselection of the Arrival Type and Platoon Ratio.

The following are PTV Vistro’s traffic signal controller results table and a short description of theparameter, as well as the Synchro Equivalent parameter, if applicable. For more detailed descriptions
and units of each parameter, visit the Vistro help under Chapter 8.

Table 2-2: Typical traffic signal controller results terminology
Parameter
Lane Group Results
X, Volume/Capacity for
Lane Groupd, Delay for LaneGroup
Lane Group LOS
Critical Lane Group
50th-Percentile Queue
Length50th-Percentile Queue
Length PTV GmbH Feb-23

Short Description

Synchro Equivalent

The ratio of the total analysis volume (flow rate) to thecapacity
Control delay for lane group

Volume to Capacity
Ratio
Control Delay

Level-of-service for lane group
Lane groups with the highest flow rate are indicated as
critical.
50th percentile queue length measured in the number ofvehicles per lane
50th percentile queue length measured in feet per lane

Level of Service
Queue Length 50th

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95th-Percentile Queue
95th percentile queue length measured in the number ofLengthvehicles per lane
95th-Percentile Queue
95th percentile queue length measured in feet per lane
LengthMovement, Approach, and Intersection Resultsd_M, Delay forControl delay per movement
Movement
Movement LOS
Level-of-service for movement
Critical Movement
The Critical movement on the approachd_A, Approach Delay
Average control delay by the approach
Approach LOS
Level-of-service for approachd_I, Intersection Delay
Average control delay for the intersection
Intersection LOS
Level-of-service for intersection
Intersection V/CVolume-to-capacity ratio for the intersection

Queue Length 95th

Approach Delay
Approach LOS
Intersection Delay
Intersection LOS
Max v/c Ratio

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4 Steps in creating signal controllers andperforming local optimization
4.1 Default Signalization
After inputting the intersection geometry, crosswalk information (if applicable), and setting the primarycontrols and methods, PTV Vistro automatically sets up the traffic signal controller. Default signalization
generates signal groups based on the control types. As a result, this will generate your Sequence andPhase Diagram for common 3 and 4-leg intersections and is the preferred signal creation method
for most intersections.

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Figure 3-1: Typical Intersection settings needed before clicking Default Signalization

Also, Default Signalization will use the timing parameters defined in Global Settings.
Furthermore, the Major and Minor street Priority Scheme determines how to allocate the NEMA traffic
signal phasing convention. This is also customizable in Global Settings. The first method of local
optimization is to just click on Default Signalization. Local optimization from Default signalization
behaves differently from the initial setup:••

The 1st time this is clicked, the splits and cycle length are locally optimized.
The 2nd time this is clicked, only the splits are optimized. The Cycle length will stay the same.

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Figure 3-2: Default Signalization sets up your traffic signals

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4.1.1

Pedestrian Clearance (Flashing Don’t Walk) Estimation

Default Signalization estimates pedestrian clearance or the flashing don’t walk (FDW) interval. First, thecalculation uses the pedestrian walking speed entered in the Intersection Settings section of the Traffic
Control workflow. These speeds are based on your agency’s recommendations and engineering
judgment.
If the Crosswalk Length is not set in the Intersection Setup workflow, PTV Vistro will automaticallyestimate the length using the roadway cross-sectional width. This feature is extremely useful forplanning situations.
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Warning messages indicate missing crosswalk length values or if the entered crosswalk value is lessthan the minim lane widths of the leg.

Figure 3-3: A sample of crosswalk warning messages

In some cases, these can be ignored; however, FDW calculated estimates should be placed withengineering-based pedestrian clearance calculations. And, crosswalk lengths should be verified andreplaced based on new lane configuration modifications, as-built designs, field measurements, and/or
measurements conducted in PTV Vistro using the measuring tool.

Figure 3-4: Using the measuring tool to determine the crosswalk length for pedestrian
clearance calculations.

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Example 3-1: Understanding Pedestrian Clearance Calculations
Impacts of crosswalk lengths can be simply tested and comparing 2 basic intersections with traffic
signals setup using default signalization.
1. Create intersection 1 and then leave the crosswalk lengths as 0 in the Intersection Setup
Workflow. Then click default signalization.
2. Create intersection 2 and then enter a crosswalk length, perhaps 2x greater than the approachleg width, in the Intersection Setup Workflow. Then click default signalization.
3. Notice the difference in pedestrian clearance and interval calculations.
4. Note the warnings on intersection 1 indicated that the crosswalk length is not entered and thevalues are less than the graphical width of the approach leg.

Figure 3-5: Pedestrian Clearance Calculation Example

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4.2 Manual Signalization setups
For non-standard 3- or 4-legged intersections configurations, intersections with more than 4 legs,intersections sharing traffic signal controllers, or requiring special signal groups, manual setup of
signals may be required.

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4.2.1

Assigning signal groups

In cases where signal groups need set manually, at new intersections, a “0” signal group will be
displayed. After setting the control types for all movements, as needed, simply enter the desired
signal group number for each movement. Entering signal groups per NEMA Phasing schemes is not
required, and you can enter any number combination.
Once the signal group is entered, the timing and advanced parameters are unlocked for further
modifications.
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4.2.2

Signal Groups Window

In the main Traffic control workflow, only 1 signal group can be used per movement along with a
combination of non-conflicting overlaps using auxiliary signal groups. However, in special cases, suchas a Texas Tight Diamond interchange functioning with 2 intersections on 1 controller (see Section
3.3.1), or a hold phase for passive transit signal priority you may need extra signal groups to workwith. These extra signal groups have a split time, can be assigned to auxiliary signal groups, added tothe sequence, and shown in the phase diagram.
To create an extra signal group, open the Signal Groups window with the Plus Icon on the Traffic
Control Toolbar. This window list all of the Signal groups assigned to the controller and indicates
which SGs are in use. Once the signal groups setup and OK is clicked, they are accessible in the Traffic
Control Workflow drop-down menus for Auxiliary Signal Groups and Sequence.

Figure 3-6: Using the signal groups window.

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4.2.3Phase diagram

The phase diagram graphically reflects the Signal Groups listed in the Phasing & Timing section andlisted in the Signal Window, but also added to the Sequence. The phase diagram lists the signal group
numbers, green, yellow, red, delayed vehicle green, pedestrian interval timing, and split information.
When hovering over a Signal Group, this information is summarized in a pop-up. Also, in this pop-up,
the Actual Green Time, and Green Time Start is displayed.
Signal Group information can be displayed in the network editor when toggling the Show Signal
Groups graphical display

to visually show what signal group belongs to what approach.

Also, the signal group bars represent the total splits for both vehicle and pedestrian signal groups andcan slide to adjust the total split time.
When the green color of the bars is lighter in color, this means that the signal group is added in thesequence, but not used locally at the active intersection. This is can because the signal group may be
used at another intersection using the same controller (creating a clustered controller case, see
Section 3.3.1) or because the signal group serves as a placeholder to reserve signal time (hold phase).
See Figure 3-6.
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Example 3-2: Create a Passive Transit Signal Priority Signal Group(Hold Phase)In this example, create a basic intersection with signal groups 2, 4, 6, and 8 – and then a special transit
signal group (SG 10) to account for a pre-timed placeholder on barrier 3 of the sequence phase
diagram.
1. Create intersection 1, set the intersection to fixed time actuation, and then click default
signalization.
2. Open the Signal Groups Window, click the “Plus” button and create Signal Group 10.
3. In Signal Group 10, enter min and max green = 3, amber = 3, all red = 1, split = 7, walk andped clearance = 0, and check max recall.
Note: With Fixed Time actuation, max recall is not needed; however, it is good practice tocheck this if the actuation method is updated later.
4. Click Ok.
5. In the sequence, enter SG 10 in Ring 1, Barrier 3.
6. In the Phasing & Timings section of the Traffic Control Workflow, adjust the splits of SG 2, 4, 6,
8 to fit SG 10 within the cycle length, or utilize the Phase diagram.

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Figure 3-7: Creating a Hold Phase Example

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4.3 Advanced Settings
4.3.1

2 or More Intersections on 1 Traffic Signal Controller

Placing 2 or more intersections under 1 controller (clustered traffic signal control) can simply beachieved by using the Controller ID drop-down list in the Intersection Setting section of the Traffic
Controller Workflow and then selecting another controller. This practice is often used with closely
spaced intersections (see Intersections 225 and 228 sharing Controller ID 225 in the Austin Texas
Example in the Help->Open Examples Directory->Signal Optimization Folder, or for a Texas Tight
Diamond, as shown in the ->Signal Controller Folder -> Tight_Diamond_Core_Overlaps forIntersections 1 and 2 sharing Controller ID 1. Additionally, many of the Examples in the ->Alternative
Intersections folder applications of this practice.
Often, the Signals Group Window will have to be utilized to set up additional Signal Groups on an
approach represented at an adjacent intersection, for example, Minor Street SG 4 at one intersectionand SG 8 at another intersection (see Section 0).
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Also, the same sequence and phase diagram are utilized at each intersection location reusing thecontroller. All Signal Groups must be placed in the sequence (from any intersection reusing thecontroller) for the signal group to be visible in the Phase Diagram. When the green color of the bars in
the Phase Diagram are lighter in color, this means that the signal group is added in the sequence, but
not used locally at the active intersection. This is can because the signal group may be used at anotherintersection using the same controller. This is very useful when setting up multiple intersections on thesame controller.
Tip#1: Utilizing the Graphic Parameter Show Intersection Info -> Controller Number
confirm which intersections share the same traffic signal controller.

will

Tip#2: Turning on the Show Signal Groups Graphic Parameter
will show the signal group
numbers per movement in the network editor. This is very useful when setting up multiple
intersections on the same controller.

4.3.2

Pedestrian fixed-time, recall, and push-button settings

Pedestrian crossing signal group in Vistro can be configured in several ways and depends on fixedtime or actuated control types. Ultimately, utilizing the Vissim Preview under Help will confirm if theconfiguration is correct.
Fixed Time: Under this configuration, pedestrian signal groups will automatically be set to recall andpedestrians will be served.
Semi-actuated: Under this configuration, the major street pedestrian signal groups will recall
automatically; however, you may choose to manually click Ped Recall for clarity. The minor street
pedestrian signal groups may operate pushbutton-stye or under recall. This choice is selected in thePedestrian Recall Checkbox in the Phasing and Timing section of the Traffic Control Workflow.
If left unchecked, the pedestrian signal group will be pushbutton controlled and only be called when apedestrian is present via a pedestrian probability calculation based on the HCM. In PTV Vissim adetector will be created to simulate the pushbutton. If this checkbox is checked, the pedestrian phase
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will recall every cycle and the signal vehicle group cannot gap out before the ped phase is complete,or the vehicle phase cannot be skipped.
Fully-actuated: Under this configuration, all pedestrian signal groups must be reviewed, requiring a
choice is in the Pedestrian Recall Checkbox in the Phasing and Timing section of the Traffic Control
Workflow.
If left unchecked, the pedestrian signal group will be pushbutton controlled and only be called when apedestrian is present via a pedestrian probability calculation based on the HCM. In PTV Vissim adetector will be created to simulate the pushbutton. If this checkbox is checked, the pedestrian phasewill recall every cycle and the signal vehicle group cannot gap out before the ped phase is complete,or the vehicle phase cannot be skipped.
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Example 3-3: Pedestrian Push button and Recall Settings
The Chapel Hill Small Corridor example under Help -> Open Examples Director -> Signal
Optimization explains showcases the pedestrian push button or recall configuration. In this example,
Intersection #1 and #2 are set to semi-actuated with pushbuttons on the north and south approach(not checked for the Pedestrian Recall parameter). Intersection #3 is fully-actuated, and all approaches
operate with a pushbutton.
For Intersection #1 in this example Reviewing Signal Groups 4 and 8’s Actual Green Time results in
the Lane Group Calculations section of the Traffic Control Workflow, it is apparent that the green timeis less than the Green time under a Fixed time Configuration.
1. Observe the northbound and southbound Actual Green Time approach results withpedestrian recall unchecked (push button). The result is 14 seconds. This means that due tothe pedestrian probability influences of a push button, some cycles truncate the green time as
expected. The extra 5 seconds of green time is given to the major street.
2. Next, On the Volume Workflow, change the pedestrians to 50 for northbound andsouthbound approaches under pedestrians (v_do and v_di inputs). Back on the Traffic
Control Workflow observe that the Actual Green Time results are now 18 seconds for both
northbound and southbound approaches, meaning that the vast majority of Cycles will receivea pedestrian push button call.
3. Finally, check the pedestrian recall box (no push button) for both the northbound andsouthbound approaches. Now, the Actual Green Time results are 19 seconds, meaning thatthe signal group is recalled to the maximum green every cycle.

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Figure 3-8: Example of Pedestrian Push Button’s influence on serviced Actual Green Time

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4.3.3

Exclusive Pedestrian Phase

PTV Vistro also includes build-in functionality to analyze exclusive pedestrian phases. Some local
names for such a phase are the Barnes Dance or Pedestrian Scramble. These phases allow allpedestrians to cross on one pedestrian phase while vehicular traffic has all-red signals. Additionally,
this safe and efficient crossing option is useful for intersections with high pedestrian crossing volumes
and multiple transit stops requiring a multi-stage crossing. See Scenario 2 in the Signalize Midblock
Crossing example located under Help -> Open Examples Director -> Pedestrian and Bicycles andthe supporting documentation.
To create this configuration, visit the Exclusive Pedestrian Phase section of the Traffic Control
Workflow, create a pedestrian signal group, assign a pedestrian walk time and clearance, and then
add the signal group into the sequence. Once added here, the Phase Diagram will display the
Exclusive Pedestrian Phase.
Note: Once an exclusive pedestrian phase is added, all other pedestrian signal group bars will
disappear and the data entry will be locked for the walk and clearance input from the Phasing andTiming section.
In some special cases, cities may need to utilize exclusive pedestrian phases along with additional
traditional approach based pedestrian phases. In this case, create an intersection with regularpedestrian crossing phases. Then create a special “placeholder” phase (hold phase) using the Signal
Group Window, as discussed in Back to top

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Example 3-2 – then add this special signal group to the sequence. This will conservatively replicate theexclusive pedestrian phases along with traditional approached based pedestrian signal groups. With
this method, all conflicting pedestrian volumes will still be allocated to the primary approach-based
pedestrian signal groups and not allocated to the hold phase. This will lead to greater impacts on thevehicle results. Currently, no HCM guidance is available for combining exclusive pedestrian phaseswith the traditional approach based pedestrian phases, and judgments should be made to interpret
analysis results.

Figure 3-9: Exclusive Pedestrian Phase Setup and Vissim Simulation

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4.3.4

Delayed Vehicle Green

Leading pedestrian intervals (LPIs) at traffic signals are wide-spread active transportation plan features.
LPIs can be achieved by requiring no additional signal phases and can utilize the Delay Vehicle Green
Parameter.
The Delayed Vehicle Green parameter in the Phasing & Timing section of the Traffic Control
Workflow Panel, inserts a red time at the start of the signal group split, as shown in the Phase
Diagram. This delays the vehicular start of green, which can be observed in the Lane Group PTV GmbH Feb-23

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Calculations section of the Traffic Control Workflow Panel. This delay time allows pedestrians andcyclists to lead.
Note: LPI modeling is setup for fixed-time controllers only. However, the delayed vehicle green
parameter can be applied to actuated pedestrian approaches, but this will call the delayed vehicle
green every cycle – even without pedestrian “calls”. Currently, no HCM guidance is available for
actuated leading pedestrian interval calculations and judgments should be made to interpret
analysis results.
Furthermore, leading pedestrian intervals are exported to PTV Vissim automatically. See the example
documentation in Help->Open Examples Directory ->Pedestrians and Bicycles -> Lead PedestrianInterval for more detailed information on how this is coded in PTV Vissim’s .RBC file via the ANM
export.
The Delay Vehicle Green parameter has other advanced applications, such as to produce a Montreal
Leading Thru or to emulate a stage-based controller in a ring-barrier environment.
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Example 3-4: Create and LPI with Delayed Vehicle GreenIn this example, create an LPI utilizing the Delayed Vehicle Green Parameter.
1. Create a basic intersection 3 leg intersection. Set 200 vehicles on each approach, on 100
pedestrians on each crosswalk.
2. Set the intersection to fixed-time and create default signalization
3. Set the Delayed Vehicle Green parameter for 10 seconds on each approach and adjust the
max green timing to compensate.
4. Under the Lane Group Calculations observe the Green Time Start results and compare themto the Phase Diagram.
5. Finally, under Simulation->Preview in Vissim observe the Leading Pedestrian Interval in
Vissim.

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Figure 3-10: Delayed Vehicle Green Settings.

Figure 3-11: PTV Vissim Leading Pedestrian Interval Simulation

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4.3.5Overlaps

Overlaps can be selected under the Signal Group’s control time for all movements. This links thesignal timing together of the parent signal group and the overlapping auxiliary signal group.
A common configuration is overlapping a protected left-turn signal group with a non-conflicting rightturn signal group.
Additionally, overlapping signal groups provide an opportunity to create a special or custom
configuration like that shown in the Texas Tight Diamond in Figure 3-6 (also shown in Help->Open
Examples Directory ->Signal Controller -> Tight Diamond Core Overlaps and described in the
documentation).
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4.3.6

Montreal’s Leading Thru Configuration with Overlaps

Also, Overlaps can be used to create leading thru phases on shared lane groups, commonly utilized inMontreal, Canada. Typically, in this case, shared-lane turns with thru movement would have the same
Permissive signal group. However, in Montreal, the thru will receive a green indication first, and theshared left and right turning vehicles are required to wait until their green indication. This is often
intended to protect crossing pedestrians, thus providing a leading pedestrian interval under thissituation.
To achieve this in Vistro, the Overlap Control Type can be assigned to the left and right movements on
the shared lanes. This unlocks the usage of Signal groups for left and right turn movements. Then, by
utilizing the Delay Vehicle Green parameter, the turns can be held in 1 signal group, while the thru
leads first in another signal group. See the following figure and example.
Note: This configuration does result in an ICA check error since the application is not conventional.
The message indicates the more than 1 signal groups control the same shared lane; however, that isexactly what needs to be achieved in this configuration. Importantly, interpretation of the results isneeded, as green time will only be calculated for the lane groups, not for each movement per HCM.
Due to this, the thru green time prevails in the lane group, as it is the highest, and the results of theturning movements are calculated with a higher green time than represented in the field conditions.
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Example 3-5: Creating Montreal’s Leading Thru Configuration with
Overlaps and Delayed Vehicle GreenIn this example, create an intersection utilizing Montreal’s leading thru configuration with Overlaps andshared turning lanes. The thru signal groups are set to 6, and the turning signal groups are set to 2
with a delayed vehicle green of 7 on each turn.
1. Create a basic intersection and set the Major Street lane configuration Shared Left/Thru andShared Thru/Right.

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2. Next, instead of creating default signalization, set the northbound and southboundmovements to both signal group 6. Then on the northbound and southbound right and left
movements, set the Control Type to Overlap.
3. Next, set the signal group for both the right and left turns to 2. Under the Auxiliary Signal
Group settings, ensure that signal group 6 is NOT checked, thus resulting in both Signal group
2 as both the parent and auxiliary.
4. Then, set minimum and maximum green, amber, red, and split times for all signal groups.
5. Then, set the Delay Vehicle Green time to 7 seconds for both the left and right turns.
6. Finally, review the pedestrian timing, coordination, recalls, detectors, and dual entry settings asneeded.

Figure 3-12: Create Montreal’s Leading Thru Configuration with Overlaps and Delayed Vehicle
Green

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4.4 Local and Automatic Optimization
After setting up the intersection settings in the traffic control tab it can be Local Optimized. Local
optimization will optimize the intersections individually, and will not consider coordination.
The first method of local optimization is to just click on Default Signalizationon the Traffic Control
Workflows toolbar (see Figure 1-3). Local optimization from Default signalization behaves differently
from the initial setup:•

The 1st time this is clicked, the splits and cycle length are locally optimized.

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•The 2nd time this is clicked, only the splits are optimized. The Cycle length will stay the same.

The second method for local optimization is to go to Signal Control -> Local Optimization. This canbe conducted before or after default signalization. In this menu, the following can be set:
•
•

•
•

Objective function strategies from “volume/Capacity balancing” or “minimizing the criticalmovement delay”.
Optimize splits only, or splits and cycle times.
o Selecting splits and cycle times unlocks an option to select a cycle length range andstep size for each iteration, as well as a try set if your intersection has a preferredcycle time array or a specific cycle length in mind.
Locally optimize all intersections
Save the settings for next time.

Figure 3-13: Local Optimization Menu

The third method is to click on the Optimize Split and Cycle Time buttonon the Traffic Control
Workflows toolbar (see Figure 1-3). Here the selection of parameters is similar to the previous
method; however, you can’t optimize all intersections.
Finally, the fourth way is to optimize locally is with the Automatic Optimization toggle
on the Traffic Control Workflows toolbar (see Figure 1-3). This optimizes the splits
only. When checked, updates to lane configurations, volumes, control types, or other timing settings
will automatically optimize the signal. When unchecked the intersection won’t optimize with each
update made. This sets Vistro apart from other software, such as Synchro where changes automatically
optimize the signal.
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4.5 Renumbering Controller IDs
Matching controller ID numbers to an agency number scheme or just organizing your traffic controller
numbers is possible in PTV Vistro. In some cases, merging in a model from another network orimporting an OpenStreetMap file may produce intersection numbers and traffic signal controller IDs
that need to be revised. Or perhaps extra intersections were created and then deleted and the orderof intersections and controller IDs need to be reordered. There are 2 methods to modify a traffic signal
controller ID number.
The first method is to simply change the Intersection Number, which can only be achieved on theIntersection Setup Workflow in the Number field. If the revised number entered is an available
Traffic Signal Controller ID number, then Vistro will automatically change the Controller ID to matchthe Intersection ID. If the Controller ID (and/or intersection number) is not available, the conflicting
controller (and/or intersection) must be temporarily reassigned to a vacant number to avoid theconflict. Renumbering a Controller ID only requires method 2.

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The second method is to go to Signal Control -> Edit Controllers… and renumber only the traffic
signal controller ID. This window provides a list of all traffic signal controllers with numbers in the ID
column which is editable to change the controller ID number. The only other editable field in this list is
the controller Description. This field enables the entry of notes about the controller, just as inspection
dates, controller manufactures, or classification types. Next, the intersection number shows where thetraffic signal controller is applied. Multiple intersection numbers indicate that the traffic signal
controller is used at multiple locations. If there are multiple locations, the intersection name will be
displayed only for the first ID. Also, the Coordination Group is displayed to show what corridor or
signal system the controller resides in. To learn more about Coordination Groups see Section 4.1.
These columns can be filtered or sorted by clicking. To filter by value, enter the value, then hold down
shift to select multiple controllers to show.

Figure 3-14: Edit Controllers Window with Location Filtering

5 Network Optimization
PTV Vistro’s powerful coordination tools can optimize entire districts, corridors, and precise routes with
our user-friendly graphical-user interface, resulting in accurate and fast Green Wave optimizations. PTV
Vistro provides you with two network optimization methods:
Traditional zonal coordination using “Coordination Groups”; andUser-defined and flexible optimization corridors using “Routes”.

5.1 Coordination Groups
In PTV Vistro, setting intersections to the same Coordination Group (similar to Zones in Synchro),
optimizes the intersections’ offsets, in addition to the cycles and splits, if desired. This zonal
optimization calculates the Green Wave between intersections in that Coordination Group. Using
multiple Coordination Groups can optimize a combination of districts and corridors as individual
groups, or all at the same time using basic equal coordination to a City grid or straight-line corridors.
By default, 1 Coordination Group is included in a new Vistro file; however, more can be added.

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Note: A Coordination Group must be assigned to an intersection to be considered for Network
Optimization. If a Coordination Group is not assigned, the intersection will not be recognized in the
Network Optimization process.
Tip: To increase efficiency when modeling, it is best to have all signal coordination groups created if
known ahead of time, then allocated Coordination Groups can be achieved while creating andmodifying traffic signal controllers.
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5.1.1

Create a Coordination GroupTo view, add, or modify the Coordination Groups, go to Signal Control -> Edit Coordination groups.
In this menu:•••

New Coordination Groups are added with the plus icon
Deleted with the trash can icon ; andRenamed in the Name field.

;

Once a series of controllers are assigned a Coordination Group (see Section 0), such as along acorridor or in a city district grid, this menu can be revisited to assign a Master Intersection Controller(see Section 0).

Figure 4-1: Adding or Modifying Coordination Groups->

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5.1.2

Assign Coordination GroupTo assign a Coordination Group to each intersection, click on the intersection, navigate to the Traffic
Control Workflow, and then select the drop-down list from the Signal Coordination Groupparameter – and then select the desired Coordination Group.

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Figure 4-2: Assigning a Coordination Group to an Intersection

Tip #1: To identify the Coordination Group set on each intersection in the network editor, click on theShow Intersection Info graphic parameter and select the Coordination Group option. This will
display which intersections have been assigned a group and help provide a quick quality control
check. If a group is not assigned to an intersection, the intersection will be blank.
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5.1.3

Selecting a Master Controller

Selecting a Master Controller in the Coordination Group is optional to network optimization; however,many agencies prefer to introduce a master controller clock within a series of coordinated signals. If
an intersection is set to the Master Controller, the offset reference is locked to 0 seconds when set.
All other controllers in the same Coordination Group will adjust relative to the Master Controllers 0
second offset automatically.
Tip #1: To identify the intersection controller number in the network editor, click on the Show
Intersection Info graphic parameter and select the Controller Number option.
Tip #2: To identify the Coordination Group set on each intersection in the network editor, click on theShow Intersection Info graphic parameter and select the Coordination Group option.
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Example 4-1: Creating and Assigning a Coordination Group, andselecting a Master Controller
This example, will create a Coordination Group, assign it to a series of intersections, and select anintersection Master Controller.
1. First, go under Signal Control -> Edit Coordination groups to add a new coordination group.
Click on the plus icon to create Coordination Group 2. Name the coordination group“Example”. Then click “OK” to save the Coordination Group.
2. Next, Create 2 closely spaced intersections then connect adjacent Leg Handles.
3. Next, go under Signal Control -> Default Signalization. Then, click on “Create Default
Signalizations” to create Signal Groups for each intersection simultaneously.

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4. Notice at each intersection the Signal Coordination Group parameter shows a “-“, indicatingthat no Coordination Group is defined. Define Coordination Group 2 for each intersection.
5. Turn on the Graphic Parameter Show Intersection Info -> Coordination Group and confirm
that both intersections are on Coordination Group 2.
6. Place a 3rd intersection, using copy and paste to the right of the right-most intersection (Rightclick on the main Intersection Grip to open the context menu, select Copy Intersection, andthen right-click on a location to Paste the Intersection using the context menu.
7. Notice that this intersection is already assigned Coordination Group 2 when using copy andpaste. This could be used as a shortcut when setting up intersections.
8. Connect the new intersection’s Leg Grip with the middle intersection.
9. Turn on the Graphic Parameter Show Intersection Info -> Controller Number and determine
the Controller ID of the right-side intersection. Renumber the signal controller ID numbers, as
needed (see Section 0).
10. Click on each intersection and enter the Offset values of “5, 10, and 15” seconds from left toright, for each intersection under the Intersection Settings section in the Traffic Control
Workflow. Leave the rightmost intersection active, with the Offset value viewable in theIntersection Settings section.
11. Go to Signal Control -> Edit Coordination groups, select Coordination Group #. Under the
Master Controller drop-down list select the rightmost intersections Controller ID number.
Before clicking “ok” to accept the changes, take note of the Offset value in the Intersection
Settings section set for 15 seconds.

Figure 4-3: Assigning a Master Controller in a Coordination Group.

12. Then, click “OK”. Notice that the Offset value change to 0 seconds. This value will be locked.
Note: the new Offset values calculated for the other “non-master” intersections.
13. Go back to the rightmost intersection, and attempt to change the Offset value to somethingother than 0. Note, the error by hovering over the red “X”. This value can not be updated
since the controller is the master.

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5.2 Network Optimization Settings and Running
After Coordination Groups are created, the network and be optimized Using the Network Optimization
tools in PTV Vistro. Go to Signal Control -> Network optimization, to open the Network
Optimization Settings menu. This menu has the following parameters with descriptions. Moreinformation can be found in the Vistro Help manual under the Help menu:

Table 4-1: Network Optimization Settings and Description
Parameter

Short Description

Objective function

In these fields, the weights for delays and stops can be defined The formula isused to determine the Performance Index for optimization. Generally, thestop weight is a low number because this is the total number of stops acrossthe intersections being optimized.

Genetic method

This method is a more robust and customizable method that includes closing
criteria The maximum number of iterations can be selected as well as
Population Size. Generally speaking, the larger the population size the betterthe optimum solution. The number of runs without improvement and an
improvement percentage threshold represent the closing criteria to themethod.

Hill Climb method

This method is a simpler and faster method but the optimization may close
without finding the optional solution if the number of runs is low. Here the hill
climb defaults to only 10 starting solutions and genetic defaults to 100
iterations with the closing criteria.

Coordination Groups to
Be Optimized

One, more, or All Coordination groups can be selected. To select a few
groups hold down SHIFT and click.

Optimize Split and/or
Cycle Time

Here, choose if to optimize, Splits Only, or Splits and Cycle Time. And if
you only want to optimize offsets just leave the splits and cycles unchecked.
When selecting Splits and Cycle Time and upper and lower bound, alongwith step size can be entered.

Use Offset Optimization

Choose if the Offsets between traffic signal controllers should be optimized
and the precision of the optimization.

Allow Lead/Lag
Optimization

Optimization will find the best solution for the left-turns in either a leading or
lagging configuration. If your agency does not allow lags, then just leave it
unchecked so all of your signal group control types on your left-turns will stayas Lead.
Note: This setting is dependent on if the Allow Lead/Lag Optimization
checkbox is checked in the Phasing and Timing Section of the Traffic
Control Workflow. If the box is checked here, then the optimization ispossible. If it is not checked, then Lead/Lag optimization for that intersection
is not available.

Save Settings

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After modifying the parameters on the Network Optimization Menu, click
Save Settings to retain your preferences.
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Run Optimization

After modifying the parameters on the Network Optimization Menu, click Run
Optimization to start the Network Optimization Process.

Figure 4-4: Network Optimization Menu

Also, the Network Optimization window is accessible in the Network Optimization Workflow’s, by
clicking the Network Optimization button. This workflow is discussed in more detail in Section 0.
Network Optimization process begins after the Run Optimization is clicked. The Optimization
Progress window will appear cycling through optimization calculations probing each specified cycle
length. The Best Score will be displayed during the optimization process based on the objectivefunction. The lowest Cycle length with the Best Score will be selected.
Note: Depending on the optimization settings, closing criteria, network size, and the number of
Coordination Groups selected at 1 time, Network Optimization could be quick or take a few minutes toprocess. It is recommended that you save your file (or a copy of your file) before running
Network Optimization in case you wish to exit the process. Occasionally, the screen will remain black PTV GmbH Feb-23

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for a few moments or show as non-responsive. Be assured, optimization is working in the background,and your patients may be required for larger networks. Using the Allow Reduction of Optimum Split
and Minimum Improvement parameters greatly increases processing time.

Figure 4-5: Network Optimization Progress Window

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5.3 Routing
PTV Vistro’s Traffic Signal Optimization Routes enhances a Coordination Group’s Green Wave
optimization by taking the traditional methodology further. With Routes, you can optimize a corridor
that makes a turn or has a higher priority Weight over another route.
A typical application of Optimization Routes is identifying several corridors by drawing a Route object,
and then optimizing it with or without assigned priority weights within a City grid or district
Coordination Groups. This will establish key arterial corridors within the Coordination Group – andincreased functionality over traditional zonal coordination, by tying a series of movements together.
Also, Routes are necessary to visualize the Time-Space Diagram shown on the Network Optimization
Workflow (see Section 0).
To draw a route, left-click the Route button, and then start with the Leg End or Intersection Gripat one end of the network and drag to another Leg End or Intersection Grip, and double left-click tocomplete the Route. A route can also be manually defined by left-clicking once on each Intersection
Grip until the last point, ending the Route with a double left-click. Routes can also be redefined by
dragging the intermediate points to another intersection with a left-click. More information on drawing
routes can be found in the Turning Routes 2-Way to 1-Way Conversion example documentation
located under Help->Open Examples Directory ->Signal Optimization folder. After the Route is
created it will be displayed in the Network Optimization Workflow (see Section 0).
Additionally, the linked video indicates how the draw a route: Drawing a Route.

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Figure 4-6: Drawing a Traffic Signal Optimization Route

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5.4 Network Optimization Workflow and Time-Space Diagrams
The Network Optimization Workflow
summarizes every Route in the network (see Section0), and the Time-Space Diagram along that Route and/or Reverse Route. With at least 1 Routedefined, the Network Optimization Route table will be populated. Here a Name can be given to the
Route, typically indicating the direction as well as a Weight. The weight is a factor that gives priority
to the Routes movements at each intersection in Network Optimization. The higher the Weight, thehigher the priority.
A Routes Reverse Direction can be quickly created by right-clicking on the route in the table toopen the context menu. This will create an exact copy of the route. When creating a reverse direction,
be aware of one-way roadways. Also, this context menu contains an option to Delete the Route or PTV GmbH Feb-23

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Copy and Paste route text. Copy and Paste do not copy the Route. An example of Route Setup,
Reverse Directions, and with Weights is shown in the Atlanta TIA Mitigate example under Help->Open
Examples Directory ->TIA.
The following are additional parameters of the Network Optimization Workflow as shown with labels in
Figure 4-7:
1. The Time-Space Diagram can be visualized using the Maximum Flows or Arterial Bands in
the Signal Time-Space Diagram Mode drop-down menu.
2. The scale of the Time-Space Diagram can be set with the Max Signal Time(s) parameter.
3. The Time-Space Diagram can show the Route in the Reverse Direction if one is created bychecking the Show Reverse Direction route.
The Time-Space Diagram also shows the following information.
4. Spacing between intersections along the Route.
5. Intersection and Controller ID numbers, and the
6. Cycle Time, Offset, and Coordination Group number

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Figure 4-7: Time-Space Diagram on the Network Optimization Workflow

Additionally, Time-Space Diagrams can be printed by going to File -> Print report. On the “SelectReport” tab, select the Time-Space Diagram report under the Graphical Reports section on the rightside of the window.
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6 Additional Special Cases
6.1 Transit or Bicycle Active TSP
Transit queue-jumps utilize short, dedicated lanes. In these lanes, transit vehicles move to a priority
position and bypass queued vehicles on the approach. Once in position, detection places a priority
call to the transit signal group. Estimating active TSP in Vistro provides a general understanding ofqueue jump operations. This begins by adding a special transit leg to access traffic volumes anddetection parameters.
Furthermore, importing PTV Vistro into PTV Vissim or Visum migrates your special transit leg,detection, and signal groups into an advanced transit planning tool. These advanced transit planning
toolsets include TSP elements, such as phase omits, minor street truncations, and signal corridor
coordination. The following video tutorial shows how to create active TSP in PTV Vistro, building fromthe passive TSP example:
Active TSP estimation in PTV Vistro

Figure 5-1: Transit or Bicycle Active TSP Self-Tutorial (click for video)

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7 Migration from Synchro
7.1 Global Settings
Make sure global settings are complete before Merging a Synchro file. See Section 1.1 forrecommendations. More Information Coming Soon PTV GmbH Feb-23

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Back to top

7.2 Importing a Combined .csv
Information Coming Soon
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7.3 Merge
Information Coming Soon
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7.4 Update
Information Coming Soon
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