There are various applications that can be used to define vehicular demand for SUMO. Of course it is also possible to define the demand file manually or to edit generated files with a text editor. Before starting, it is important to know that a vehicle in SUMO consists of three parts:

• a vehicle type which describes the vehicle's physical properties,
• a route the vehicle shall take,
• and the vehicle itself.

Both routes and vehicle types can be shared by several vehicles. It is not mandatory to define a vehicle type. If not given, a default type is used. The driver of a vehicle does not have to be modelled explicitly. For the simulation of persons which walk around or ride in vehicles, additional definitions are necessary.

Vehicles and Routes

Initially, we will define a vehicle with a route owned by him only:

<routes>
   <vType id="type1" accel="0.8" decel="4.5" sigma="0.5" length="5" maxSpeed="70"/>

   <vehicle id="0" type="type1" depart="0" color="1,0,0">
      <route edges="beg middle end rend"/>
   </vehicle>

</routes>

By giving such a route definition to SUMO (or SUMO-GUI), SUMO will build a red (color=1,0,0) vehicle of type "type1" named "0" which starts at time 0. The vehicle will drive along the streets "beg", "middle", "end", and as soon as it has approached the edge "rend" it will be removed from the simulation.

This vehicle has its own internal route which is not shared with other vehicles. It is also possible to define two vehicles using the same route. In this case the route must be "externalized" - defined before being referenced by the vehicles. Also, the route must be named by giving it an id. The vehicles using the route refer it using the "route"-attribute. The complete change looks like this:

<routes>
   <vType id="type1" accel="0.8" decel="4.5" sigma="0.5" length="5" maxSpeed="70"/>

   <route id="route0" color="1,1,0" edges="beg middle end rend"/>

   <vehicle id="0" type="type1" route="route0" depart="0" color="1,0,0"/>
   <vehicle id="1" type="type1" route="route0" depart="0" color="0,1,0"/>

</routes>

A vehicle may be defined using the following attributes:

Repeated vehicles (Flows)

It is possible to define repeated vehicle emissions ("flow"s), which have the same parameters as the vehicle except for the departure time. The id of the created vehicles is "flowId.runningNumber" and they are distributed either equally or randomly in the given interval. The following additional parameters are known:

<flow id="type1" color="1,1,0"  begin="0" end= "7200" period="900" type="BUS">
    <route edges="beg middle end rend"/>
    <stop busStop="station1" duration="30"/>
</flow>

Routes

One may notice, that the route itself also got a color definition, so the attributes of a route are:

There are a few important things to consider when building your own routes:

• Routes have to be connected. At the moment the simulation raises an error if the next edge of the current route is not a successor of the current edge or if the vehicle is not allowed to drive on any of the lanes. If you want the old behavior where a vehicle simply stopped at the end of the current edge and was possibly "teleported" to the next edge after a waiting time, use the Option --ignore-route-errors.
• Routes have to contain at least one edge.
• The route file has to be sorted by starting times. In fact this is only relevant, when you define a lot of routes or have large gaps between departure times. The simulation parameter --route-steps, which defaults to 200, defines the size of the time interval with which the simulation loads its routes. That means by default at startup, only routes with departure times <200 are loaded, if all the vehicles have departed, the routes up to departure time 400 are loaded etc. pp. This works only if the route file is sorted. This behavior may be disabled by specifying --route-steps 0. It is possible to load unsorted route files as an additional file which will load the whole file at once.

The first two conditions can be checked using <SUMO_HOME>/tools/route/routecheck.py, the third can be "fixed" using <SUMO_HOME>/tools/route/sort_routes.py.

Incomplete Routes (trips and flows)

Demand information for the simulation may also take the form of origin and destination edges instead of a complete list of edges. In this case the simulation performs fastest-path routing based on the traffic conditions found in the network at the time of departure/flow begin. Optionally, a list of intermediate edges can be specified with the via attribute. The input format is exactly the same as that for the DUAROUTER application and can be found here.

<routes>
  <trip id="t" depart="0" from="beg" to="end"/>
  <flow id="f" begin="0" end="100" number="23" from="beg" to="end"/>
  <flow id="f2" begin="0" end="100" number="23" from="beg" to="end" via="e1 e23 e7"/>
</routes>

For more details on how to handle routing errors and influence the routing in this case see Demand/Automatic_Routing.

For supported attributes for flows and trips see here.

Traffic assignement zones (TAZ)

It is also possible to let vehicles depart and arrive at traffic assignment zones (TAZ). This allows the departure and arrival edges to be selected from a predefined list of edges. Those edges are used which minimize the travel time from origin TAZ to destination TAZ. When loading trips into DUAROUTER the loaded travel times are used (with empty-network travel times as default). When loading trips into SUMO, the current travel times in the network are used as determined by the rerouting device.

<routes>
  <trip id="t" depart="0" fromTaz="taz1" toTaz="taz2"/>
</routes>

<additional>
   <taz id="<TAZ_ID>" edges="<EDGE_ID> <EDGE_ID> ..."/>
   ...
</additional>

When loading <taz> in SUMO-GUI the optional attribute shape can be used to draw an arbitrary polygon border for visualizing the traffic assignment zone.

A Vehicle's depart and arrival parameter

Using the depart... and arrival...-attributes, it is possible to control how a vehicle is inserted into the network and how it leaves it.

depart

Determines the time at which the vehicle enters the network (for <flow the value of begin is used instead). If there is not enough space in the network, the actual depart time may be later.

• When using option --max-depart-delay <TIME> the vehicle is discarded if unable to depart after the given delay
• A random offset to the specified depart time is added for each vehicle when using option --random-depart-offset <TIME>
• When using the special value triggered, the vehicle will depart as soon as a person enters it.

departLane

Determines on which lane the vehicle is tried to be inserted;

• ≥0: the index of the lane, starting with rightmost=0
• "random": a random lane is chosen; please note that a vehicle insertion is not retried if it could not be inserted
• "free": the most free (least occupied) lane is chosen
• "allowed": the "free" lane (see above) of those lane of the depart edge which allow vehicles of the class the vehicle belongs to
• "best": the "free" lane of those who allow the vehicle the longest ride without the need to lane change
• "first": the rightmost lane the vehicle may use

BTW, I like "best" at most - dkrajzew

departPos

Determines the position on the chosen departure lane at which the vehicle is tried to be inserted;

• ≥0: the position on the lane, starting at the lane's begin; must be smaller than the starting lane's length
• "random": a random position is chosen; it is not retried to insert the vehicle if the first try fails
• "free": a free position (if existing) is used
• "random_free": at first, the "random" position is tried, then the "free", if the first one failed
• "base": the vehicle is tried to be inserted at the position which lets its back be at the beginning of the lane (vehicle's front position=vehicle length)
• "last": the vehicle is inserted with the given speed as close as possible behind the last vehicle on the lane. If the lane is empty it is inserted at the end of the lane instead

departSpeed

Determines the speed of the vehicle at insertion;

• ≥0: The vehicle is tried to be inserted using the given speed. If that speed is unsafe, departure is delayed.
• "random": A random speed between 0 and MIN(vehicle's maximum velocity, lane's maximum velocity) is used, the speed may be adapted to ensure a safe distance to the leader vehicle.
• "max": The maximum safe velocity (speedLimit * speedFactor)
• "desired": The maximum velocity (speedLimit * speedFactor). If that speed is unsafe, departure is delayed.
• "speedLimit": The speedLimit is used. If that speed is unsafe, departure is delayed.

arrivalLane

Determines the speed at which the vehicle should end its route;

• "current": the vehicle will not change it's lane when nearing arrival. It will use whatever lane is more convenient to reach its arrival position. (default behavior)
• ≥0: the vehicle changes lanes to end it's route on the specified lane

arrivalPos

Determines the position along the destination edge where the vehicle is conisdered to have arrived;

• "max": the vehicle will drive up to the end of its final lane. (default behavior)
• <FLOAT>: the position on the lane, starting at the lane's begin; Negative values count from the end of the lane
• "random": a random position is chosen at departure; If vehicle is rerouted a new random position is selected.

arrivalSpeed

Determines the speed at which the vehicle should end its route;

• "current": the vehicle will not modify it's speed when nearing arrival. It will drive as fast as (safely) possible. (default behavior)
• ≥0: the vehicle approaches it's arrival position to end with the specified speed

Vehicle Types

A vehicle is defined using the vType-element as shown below:

<routes>
    <vType id="type1" accel="2.6" decel="4.5" sigma="0.5" length="5" maxSpeed="70"/>
</routes>

Having defined this, one can build vehicles of type "type1". The values used above are the ones most of the examples use. They resemble a standard vehicle as used within the Stefan Krauß' thesis.

<routes>
    <vType id="type1" accel="2.6" decel="4.5" sigma="0.5" length="5" maxSpeed="70"/>
    <vehicle id="veh1" type="type1" depart="0">
       <route edges="edge1 edge2 edge3"/>
    </vehicle>
</routes>

This definition is the initial one which includes both, the definition of the vehicle's "purely physical" parameters, such as its length, its color, or its maximum velocity, and also the used car-following model's parameters. Please note that even though the car-following parameters are describing values such as max. acceleration, or max. deceleration, they mostly do not correspond to what one would assume. The maximum acceleration for example is not the car's maximum acceleration possibility but rather the maximum acceleration a driver choses - even if you have a Jaguar, you probably are not trying to go to 100km/h in 5s when driving through a city.

The default car following model is based on the work of Krauß but other models can be selected as well. Model selection and parameterization is done by setting further vType-attribures as shown below. The models and their parameters are described in the following.

<routes>
    <vType id="type1" length="5" maxSpeed="70" carFollowModel="Krauss" accel="2.6" decel="4.5" sigma="0.5"/>
</routes>

Available vType Attributes

These values have the following meanings:

Besides values which describe the vehicle's car-following properties, one can find definitions of the assigned vehicles' shapes, emissions, and assignment to abstract vehicle classes. These concepts will be described in the following. Also, you may find further descriptions of implemented car-following models in the subsection #Car-Following Models.

Speed Distributions

The desired driving speed usually varies among the vehicle of a fleet. In SUMO this is modeled by a speed distribution using the attributes speedFactor or speedDev. as explained below.

Global Configuration

Instead of configuring speed distributions in a <vType> definition (as explained below), the SUMO-option --default.speeddev <FLOAT> can be used to set a global default. Seeting this value to 0 restores pre-1.0.0 behavior.

Defining speed limit violations explicitly

Each vehicle has an individual speed factor which is multiplied with the speed limit (edge speed) to determine the desired driving speed (default 1.0). A vehicle with speed factor 1.2 drives up to 20% above the speed limit whereas a vehicle with speed factor 0.8 would always stay below the speed limit by 20%. By setting attributes speedFactor and speedDev as show below this individual speed factor for all vehicles of a type can be set to a fixed value.

 <vType id="example" speedFactor="1.2" speedDev="0"

Defining a normal distribution for vehicle speeds

The desired driving speed usually varies among the vehicle of a fleet. While this could be modeled by defining a new type for each vehicle and assigning a distinct speed factor for each type (as above) this would be quite cumbersome. Instead the attribute speedFactor can also be used to sample a vehicle specific speed factor from a normal distribution. The parameter can be given as "norm(mean, dev)" or "normc(mean, dev, min, max)". Using speedFactor="normc(1,0.1,0.2,2)" will result in a speed distribution where 95% of the vehicles drive between 80% and 120% of the legal speed limit. For flows, every inserted vehicle will draw an individual chosen speed multiplier as well. The resulting values in this example are capped at 20% of speedFactor at the low end to prevent extreme dawdling and at twice the recommended speed. A vehicle keeps its chosen speed multiplier for the whole simulation and multiplies it with edge speeds to compute the actual speed for driving on this edge. Thus vehicles can exceed edge speeds. However, vehicle speeds are still capped at the vehicle type's maxSpeed.

Defining a normal distribution (old style)

An alternative way to specify speed distributions is to use numerical values for speedFactor and speedDev. In this case speedFactor defines the expected value and speedDev defines the deviation. When using this style, capping cannot be controlled and will always default to 20% and 200%. Thus the above example can also be defined as speedFactor="1" speedDev="0.1".

Additional remarks on speed distributions

Vehicle Length

Due to the work on car following models, we decided to use two values for vehicle length. The length-attribute describes the length of the vehicle itself. Additionally, the minGap-attribute describes the offset to the leading vehicle when standing in a jam.

This is illustrated in the following image:

Within the simulation, each vehicle needs - when ignoring the safe gap - length+minGap. But only length of the road should be marked as being occupied.

Abstract Vehicle Class

A SUMO vehicle may be assigned to an "abstract vehicle class", defined by using the attribute vClass. These classes are used in lane definitions and allow/disallow the usage of lanes for certain vehicle types. One may think of having a road with three lanes, where the rightmost may only be used by "taxis" or "buses". The default vehicle class is passenger (denoting normal passenger cars).

The following vehicle classes exist:

These values are a "best guess" of somehow meaningful values, surely worth to be discussed. Though, in parts, they represent classes found in imported formats. They are "abstract" in the means that they are just names only, one could build a .5m long bus.

The following vehicle deprecated classes exist for maintaining backward compatibility:

Vehicle Emission Classes

The emission class represents a certain emission class. It is defined using the emissionClass attribute. Possible values are given in Models/Emissions and its subsections.

Visualization

For a nicer visualization of the traffic, the appearance of a vehicle type's vehicles may be changed by assigning them a certain shape using the guiShape attribute. These shapes are used when setting the drawing mode for vehicles to simple shapes. The following shapes are known:

• "pedestrian"
• "bicycle"
• "motorcycle"
• "passenger"
• "passenger/sedan"
• "passenger/hatchback"
• "passenger/wagon"
• "passenger/van"
• "delivery"
• "truck"
• "truck/semitrailer"
• "truck/trailer"
• "bus"
• "bus/city"
• "bus/flexible" (8.25)
• "bus/overland" (8.25)
• "rail" (24.5)
• "rail/light" (16.85)
• "rail/city" (5.71)
• "rail/slow" (9.44)
• "rail/fast" (24.775)
• "rail/cargo" (13.86)
• "evehicle"
• "ship"

Some of these classes are drawn as a sequence of carriages. The length of a single carriage is indicated in parentheses after the type. For these types, the length of the vehicleType is used as the overall length of the train (all carriages combined). For example, a vehicle with shape rail/cargo and length 70m will have 5 carriages. The number of carriages will always be a whole number and no carriage will be shorter than the length given in brackets but may be longer to meet the length requirements of the whole vehicle. When drawing vehicles with raster images, the image will be repeated for each carriage.

In addition, one can determine the width of the vehicle using the attribute width. When using shapes, one should consider that different vehicle classes (passenger vehicles or buses) have different lengths. Passenger vehicles with more than 10m length look quite odd, buses with 2m length, too.

Car-Following Models

The car-following models currently implemented in SUMO are given in the following table.

Car-Following Model Parameters

Mostly, each model uses its own set of parameters. The following table lists which parameter are used by which model(s). Details on car-following models and their parameters can be found here.

To select a car following model the following syntax should be used:

    <vType id="idmAlternative" length="5" minGap="2" carFollowModel="IDM" tau="1.0" .../> 

Default Krauss Model Description

The default model is a modification of the model defined by Stefan Krauß in Microscopic Modeling of Traffic Flow: Investigation of Collision Free Vehicle Dynamics. The implemented model follows the same idea as that of Krauß, namely: Let vehicles drive as fast as possibly while maintaining perfect safety (always being able to avoid a collision if the leader starts braking within leader and follower maximum acceleration bounds). The implemented model as in <SUMO_HOME>/src/microsim/cfmodels/MSCFModel_Krauss.cpp has the following differences:

• Different deceleration capabilities among the vehicles are handled without violating safety (the original model allowed for collisions in this case)
• The formula for safe velocity was adapted to maintain safety when using the Euler-position update rule. This was done by discretizing some of the continuous terms. The original model was defined for the Ballistic-position updated rule and would produce collisions when using Euler. See also Simulation/Basic_Definition#Defining_the_Integration_Method.

Lane-Changing Models

The lane-changing models currently implemented in SUMO are given in the following table.

Mostly, each model uses its own set of parameters. The following table lists which parameter are used by which model(s).

The parameters are set within the <vType>:

    <vType id="myType" lcStrategic="0.5" lcCooperative="0.0"/> 

Junction Model Parameters

The behavior at intersections may be configured with the parameters listed below.

The parameters are set within the <vType>:

    <vType id="ambulance" jmDriveAfterRedTime="300" jmDriveAfterRedSpeed="5.56"/> 

Impatience

The impatience of a driver is value between 0 and 1 that grows whenever the driver has to stop unintentionally (i.e. due to a jam or waiting at an intersection). The impatience value is computed as

 MAX(0, MIN(1.0, baseImpatience + waitingTime / timeToMaxImpatience))

Where baseImpatience is configured by setting the vType-attribute impatience and timeToMaxImpatience is set using the option --time-to-impatience (default 300s). The value of baseImpatience may negative to slow the growth of the dynamically computed impatience. It may also be defined with the value off to prevent drivers from becoming impatient.

The impatience value is used to represent a drivers willingness to impede vehicles with higher priority. At a value of 1 or above, the driver will use any gap that is safe in the sense of collision-avoidance even if it means that another vehicle has to brake as hard as it can. At a value of 0, the driver will only perform maneuvers that do not force other vehicles to slow down. Intermediate values interpolate smoothly between these extremes.

Default Vehicle Type

If the type attribute of a vehicle is not defined it defaults to "DEFAULT_VEHTYPE". By defining a vehicle type with this id (<vType id="DEFAULT_VEHTYPE" ..../>) the default parameters for vehicles without an explicititly defined type can be changed. The change of the default vehicle type needs to occur before any reference to the type was made, so basically before any vehicle or vehicle type was defined. So it should always be at the top of the very first route file.

Route and vehicle type distributions

Instead of defining routes and vTypes explicitly for a vehicle SUMO can choose them at runtime from a given distribution. In order to use this feature just define distributions as following:

Vehicle Type Distributions

<routes>
    <vTypeDistribution id="typedist1">
        <vType id="type1" accel="0.8" length="5" maxSpeed="70" probability="0.9"/>
        <vType id="type2" accel="1.8" length="15" maxSpeed="50" probability="0.1"/>
    </vTypeDistribution>
</routes>

Using existing types

<routes>
    <vType id="type1" accel="0.8" length="5" maxSpeed="70" probability="0.9"/>
    <vType id="type2" accel="1.8" length="15" maxSpeed="50" probability="0.1"/>
    <vTypeDistribution id="typedist1" vTypes="type1 type2"/>
</routes>

Route Distributions

<routes>
    <routeDistribution id="routedist1">
        <route id="route0" color="1,1,0" edges="beg middle end rend" probability="0.9"/>
        <route id="route1" color="1,2,0" edges="beg middle end" probability="0.1"/>
    </routeDistribution>
</routes>

A distribution has only an id as (mandatory) attribute and needs a probability attribute for each of its child elements. The sum of the probability values needs not to be 1, they are scaled accordingly. Note, that probability defaults to 1.00 when not specified. At the moment the id for the children is mandatory, this is likely to change in future versions.

A distribution can be used just as using individual types and routes:

<routes>
   <vehicle id="0" type="typedist1" route="routedist1" depart="0" color="1,0,0"/>
</routes>

Stops

Vehicles may be forced to stop for a defined time span or wait for persons by using the stop element either as part of a route or a vehicle definition as following:

<routes>
    <route id="route0" edges="beg middle end rend">
        <stop lane="middle_0" endPos="50" duration="20"/>
    </route>
    <vehicle id="v0" route="route0" depart="0">
        <stop lane="end_0" endPos="10" until="50"/>
    </vehicle>
</routes>

The resulting vehicle will stop twice, once at lane middle_0 because of the stop defined in its route and the second time because of the stop defined in the vehicle itself. The first stop will last 20 seconds the second one until simulation second 50. For a detailed list of attributes to stops see below. For a description on how to use them to simulate public transport see Simulation/Public Transport.

Stops can be childs of vehicles, routes, persons or containers.

• If "duration" and "until" are given, the vehicle will stop for at least "duration" seconds.
• If "duration" is 0 the vehicle will decelerate to reach velocity 0 and then start to accelerate again.
• If "until" is given and "duration" is not and the vehicle arrives at the stop at or after the time step defined by "until" it will decelerate to speed 0 and then accelerate again.
• If persons board the vehicle, the stop is extended by the "boardingDuration" of the vehicle or until the "personCapacity" is reached. (or "loadingDuration" and "containerCapacity" for containers).
• If until is defined in the context of a repeated vehicle insertion (flow) it will be incremented by the difference of vehicle creation time and "begin" of the flow.
• If neither "duration" nor "until" are given, "triggered" defaults to true. If "triggered" is set to false explicitly the vehicle will stop forever.
• if "duration" or "until" are given along with "triggered", then the vehicle will stop until the given duration/until is reached and a person has boarded
• If "parking" is set to true. The vehicle stops besides the road without blocking other vehicles.

Colors

A color is defined as red,green,blue or red,green,blue,alpha either in a vehicle, route or vType.

<route id="r0" color="0,255,255"/>
<type id="t0" color="0,0,255"/>
<vehicle id="v0" color="255,0,0,0"/>

In the default visualization settings the vehicle color will be used if define, otherwise the type and finally the route color. These settings can be changed.

By default color components should be given as integers in the range of (0,255) but other definitions are also supported:

color="0.5, 0.5, 1.0"
color="#FF0000"
color="red"

The transparency value (alpha) only takes effect when also using the vType attribute imgFile.

Devices

Vehicle devices are used to model and configure different aspects such as output (device.fcd) or behavior (device.rerouting).

The following device names are supported and can be used for the placeholder <DEVICENAME> below

• emission
• battery
• btreiver
• btsender
• rerouting
• ssm
• toc
• driverstate
• fcd
• example

Automatic assignment

Some devices are assigned automatically. Every <trip> that is loaded into the simulation is automatically equipped with a rerouting device to perform the initial route computation.

Other devices such as fcd are assigned automatically when the option --fcd-output is set.

Assignment by global options

Devices can be configured globally for all vehicles in the simulation by setting the option --device.<DEVICENAME>.probability (i.e.) --device.fcd.probability 0.25 This will equip about a quarter of the vehicles with an fcd device (each vehicle determines this randomly with 25% probability) To make the assignment exact the additional option --device.<DEVICENAME>.deterministic can be set Another option is to pass the list of vehicle ids that shall be equipped using the option --device.<DEVICENAME>.explicit <ID1,ID2,...IDk>.

Assignment by generic parameters

Another option for assigning devices for vehicle types or individual vehicles is by using generic parameters. This is done by defining them for the vehicle or the vehicle type in the following way:

<routes>
    <vehicle id="v0" route="route0" depart="0">
        <param key="has.<DEVICENAME>.device" value="true"/>
    </vehicle>

    <vType id="t1">
        <param key="has.<DEVICENAME>.device" value="true"/>
    </vType>

    <vehicle id="v1" route="route0" depart="0" type="t1"/>
</routes>