---
title: Introduction to demand modelling in SUMO
---

After having generated a network, one could take a look at it using
[sumo-gui](../sumo-gui.md), but no cars would be driving around.
One still needs some kind of description about the vehicles. This is
called the *traffic demand*. From now on we will use the following
nomenclature: A **trip** is a vehicle movement from one place to another
defined by the starting edge (street), the destination edge, and the
departure time. A **route** is an expanded trip, that means, that a
route definition contains not only the first and the last edge, but all
edges the vehicle will pass. [sumo](../sumo.md) and
[sumo-gui](../sumo-gui.md) need routes as input for vehicle
movements. There are several ways to generate routes for SUMO. The
choice depends on your available input data:

## Using trip definitions

  As described above, each trip consists at least of the starting and
  the ending edge and the departure time. This is useful for when you
  want to create *demand* by hand or when writing your own scripts to
  import custom data. You may either use
  [duarouter](../duarouter.md) to turn your trips into routes.
  See
  [Demand/Shortest_or_Optimal_Path_Routing](../Demand/Shortest_or_Optimal_Path_Routing.md)
  and
  [Demand/Dynamic_User_Assignment](../Demand/Dynamic_User_Assignment.md),
  or you may load the trips directly into [sumo](../sumo.md)
  [(more details)](../Demand/Automatic_Routing.md).

## Using flow definitions

  This is mostly the same approach as using trip definitions, but one
  may join vehicles having the same departure and arrival edge using
  this method

## Using Randomization

  This is a quick way to get some traffic if you do not have access to
  any measurements but the results are highly unrealistic. See
  [Tools/Trip\#randomTrips.py](../Tools/Trip.md#randomtripspy)

## Using OD-matrices

  Origin-Destination-Matrices (or OD-matrices) are often available
  from traffic authorities. They have to be converted to trips using
  [od2trips](../od2trips.md). See
  [Demand/Importing_O/D_Matrices](../Demand/Importing_O/D_Matrices.md),
  [Demand/Shortest_or_Optimal_Path_Routing](../Demand/Shortest_or_Optimal_Path_Routing.md)
  and
  [Demand/Dynamic_User_Assignment](../Demand/Dynamic_User_Assignment.md).

## Using flow definitions and turning ratios

  One may also leave out the destination edges for flows and use
  turning ratios at junctions instead. See
  [jtrrouter](../jtrrouter.md).

## Using detector data (observation points)

  Induction loops and similar devices are commonly used by authorities
  to measure traffic. See [Demand/Routes_from_Observation_Points](../Demand/Routes_from_Observation_Points.md).

## By hand

  You can of course generate route XML-files by hand. See
  [Definition_of_Vehicles,_Vehicle_Types,_and_Routes](../Definition_of_Vehicles,_Vehicle_Types,_and_Routes.md).

## Using population statistics

  The program [activitygen](../activitygen.md) can be used to
  turn population statistics into traffic demand. See
  [Demand/Activity-based Demand
  Generation](../Demand/Activity-based_Demand_Generation.md).

## Using data from other sources

  see [SUMO_User_Documentation\#Demand_Modelling](../index.md#demand_modelling)

By now, the SUMO-package contains four applications for generating
routes. [duarouter](../duarouter.md) is responsible for importing
routes or their definitions from other simulation packages and for
computing routes using the shortest-path algorithm by Dijkstra.
Additionally, in combination with the simulation, the
[duarouter](../duarouter.md) can compute the dynamic user
assignment formulated by C. Gawron.  [od2trips](../od2trips.md) helps
you to convert OD-matrices (origin/destination-matrices) into trips.
There are various tools to [import](../Tools/Detector.md#mapdetectorspy) and [process](../Demand/Routes_from_Observation_Points.md) local observations (i.e. counts or turning ratios)
and the most comprehensive tools of these is [routeSampler](../Tools/Turns.md#routesamplerpy).

## Notes
* With use of netedit it is possible to observe the demand amount distribution of edge-based or TAZ-based relations [network/TAZ related data](../Netedit/editModesData.md).
