Demand/Introduction to demand modelling in SUMO
After having generated a network, one could take a look at it using SUMO-GUI, but no cars would be driving around. One still needs some kind of description about the vehicles. 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 and SUMO-GUI need routes as input for vehicle movements. There are several ways to generate routes for SUMO:
- Using trip definitions
- As described above, each trip consists at least of the starting and the ending edge and the departure time
- 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 flow definitions and turning ratios
- One may also leave out the destination edges for flows and use turning ratios at junctions instead
- OD-matrices have to be converted to trips, first, then from trips to routes
- By hand
- You can of course generate route files by hand
- Using random routes
- This is fast way to fill the simulation with life, but nothing that has something to do with reality
- This method is called activity-based demand modelling
- By importing available routes
By now, the SUMO-package contains four applications for generating routes. DUAROUTER 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 can compute the dynamic user assignment formulated by C. Gawron. JTRROUTER may be used if you want to model traffic statistically, using flows and turning percentages at junctions. OD2TRIPS helps you to convert OD-matrices (origin/destination-matrices) into trips. The DFROUTER computes routes from given observation point measures.