Supply parameters

Defines the maximum jam density on links, measured in [veh/m], to make backward propagation.

After JMAX the backward propagation is skipped.

Infinite storage capacity is assumed and it is possible to manage unlimited vertical queuing on the link.

Default is 1000.

Defines the minimum wave speed, measured in [km/h], on the fundamental diagram.

The slower the waves are, the closer the flow is to the maximum capacity.

A faster wave speed implies a shorter time window to be analyzed.

MinWaveSpeed enables you to reduce both the amount of memory needed to store the H and G cumulative flows (see → Link model), and their computation time.

On the other side, this affects the shape of non-linear branches, setting a constant derivative equal to this value on the upmost part of the fundamental diagram.

This introduces a distortion, that can be ignored for small values of MinWaveSpeed.

Default is 3.6 (= 1 m/s).

Controls the final node delay model on links that have a constant delay (ITIM) or that have a signal information at link level (CYCL, GREN, see → Defining links).

Admitted values.

• 0 = Ignore delays and implicit signals.

• 1 = Fundamental diagram distortion.

  Modifies the fundamental diagram so that the signal is considered, both in terms of additional travel time and in terms of capacity reduction.

• 2 = Shift hypocritical wave arrival time.

  Does not modify the original fundamental diagram, but considers some additional hypocritical travel time.

Default is 2.

Defines the number of parallel simulation threads.

You can use this option to reduce the computation time.

Special values:

• 0 = Use single thread.
• −1 = Use as many threads as there are cores on the machine (see Windows Task Manager > Performance tab).

Default is -1.

Controls the representation of traffic signals in the simulation.

Admitted values:

• 0 = Constant green share. Signalized arcs are modeled with a constant capacity reduction, according to their green share.

• 1 = Pulsing. Signalized arcs are modeled with null exit capacity during the red light of each cycle and with full exit capacity during green light.

Default is 1.

TRE is able to manage different dynamic programs (→ Signal control events), starting form the SignalPulse value.

If SignalPulse=0:

1. .sig files (inputs for TDE) are ignored.
2. TRE calculates a constant green share (capacity reduction) for each maneuver, also if is set the green/red alternation rule.
3. TRE can manage events of type StreetSignalAction but also a DynamicInterstageProgram, and in this case it works as indicated in the point 2.

If SignalPulse=1:

1. .sig files, containing the controller information, are considered.
2. TRE represents the red/green traffic light at each simulation instant provided that the program: if the program only defines the green share associated with each maneuver, TRE uses the green share (it can not invent the green/red alternation).

If you set SignalPulse=1, the → Butterworth anti-aliasing filter is automatically set.

Duration, measured in seconds [s], of simulation intervals.

SimIntD is the duration of the elementary time intervals in the supply simulation.

The propagation of the flow is done according to this time interval. The travel time of a wave along each link can not be shorter than SimIntD.

Default is 6.

Determines whether to perform multimodal or monomodal supply simulation.

Admitted values:

• 0 = Merge modes into equivalent flow (monomodal).
• 1 = Separate modal flows.

A multimodal simulation requires higher computation time but each mode is explicitly simulated and the results can be differentiated per mode.

A monomodal simulation is faster. All the modal flows are converted into a unique equivalent flow and then results are only computed per equivalent vehicles.

This affects also internal results:

• In multimodal, the simulation can return different modal travel times.
• In monomodal, vehicles are propagated together and the travel time is the same for all vehicles that entered at the same time.

Important:  Currently, multimodal simulation does not support non-linear fundamental diagram branches. If the simulation is multimodal, the shape of fundamental diagram of all links is converted to triangular.

Default is 0.

Handles the increase of the arc length, if necessary, when you adopt the GLTM supply model.

In some cases, it is necessary to increase the arc length to ensure waves not faster than simulation speed (based on simulation clock).

In GLTM simulation a wave cannot propagate in less time than SimIntD and you can satisfy this constraint in two ways:

• Decreasing waves speed.
• Increasing the length of the arcs.

StretchArcs sets:

• false: Decrease waves maximum speed.This may alter the resulting maximum flow value on the arc.
• true: Increase arc length.

Default is true.

When StretchArcs=true the effects can be associated to UDAs described through a .net file as shown in the example:

$VISION
* Inhouse License (Productive)
* 04/20/21
* 
* Table: Version block
* 
$VERSION:VERSNR;FILETYPE;LANGUAGE;UNIT
12;Net;ENG;KM

* 
* Table: User-defined attributes
* 
$USERATTDEF:OBJID;ATTID;CODE;NAME;VALUETYPE;MINVALUE;MAXVALUE;DEFAULTVALUE;DEFAULTSTRINGVALUE;COMMENT;MAXSTRINGLENGTH;NUMDECPLACES;DATASOURCETYPE;FORMULA;SCALEDBYLENGTH;CROSSSECTIONLOGIC;CSLIGNORECLOSED;SUBATTRS;CANBEEMPTY;OPERATIONREFERENCE
LINK;ADD_LENG;add_leng;add_leng;LongLength;MIN;MAX;;;;0;3;Formula;IF([GLTM_MIN_LENG]>[LENGTH]:[GLTM_MIN_LENG]-[LENGTH]:0);0;SUM;0;;1;
LINK;ADD_TT;add_tt;add_tt;TimePoint;0;MAX;;;;0;0;Formula;([ADD_LENG]/[V0PRT])*3600;0;SUM;0;;1;
LINK;GLTM_MIN_LENG;GLTM_MIN_LENG;GLTM_MIN_LENG;LongLength;MIN;MAX;;;;0;3;Formula;[V0PRT]*12/3600;0;SUM;0;;1;

The .net file can be used to add 3 UDAs attributes to the Visum model.

The first attribute is identified by the row starting with LINK;ADD_LENG;add_leng;, indicating the new length of the link.

The second attribute is identified by the row starting with LINK;ADD_TT;add_tt;, indicating the additional length added.

The third attribute is identified by the row starting with LINK;GLTM_MIN_LENG;GLTM_MIN_LENG;, indicating the travel time on that additional length.