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Re: [sumo-user] Macroscopic traffic flow - is it possible with SUMO?
- What gives you the impression that MAROUTER creates assignment zones? The zones are read from the input using the option -d (--additional-files).
- The capacityConstraint function computes travelTime for that edge taking into account capacity constraints.
- Using the default 'incremental' method, the vehicles are assigned in chunks (total flow per OD-relation divided by number of iterations, default 20). The more vehicles that have used a link the slower it gets and this can lead to the assignment of fewer vehicles in the next step of the iteration. Vehicles always take the fastest route using the known capacities in their iteration step.

regards,
Jakob

Am Mo., 10. Dez. 2018 um 19:47 Uhr schrieb Michał Lis <johny1614@xxxxxxxxx>:
Thanks for the reply.
As I've observed - MAROUTER creates those traffic assignment zones and routes between them.
Every edge has a capacity defined by a getCapacity function (based on roadclass and length etc.).
Capacity constraint function is used to calculate travel time if we would like to travel on this edge (it is based on road's capacity, flow, speed limit etc).
This name confuses me - like shouldn't it be "getEdgeTravelTime" instead? Or is it a constraint actually on travel time because of capacity contraints?
Function incremental for all edges calculates travel times and attaches to it.
If im not mistaken we take the best route by cost which depends mainly to travel times of the edges - same as water or gas would choose way to spread.
In the end we still count each vehicle separately but direct them basing on those kinda macroscopic calculations from above? Is that the whole idea?

pon., 10 gru 2018 o 08:06 Jakob Erdmann <namdre.sumo@xxxxxxxxx> napisał(a):
Hello,
MAROUTER uses a hard-coded capacity-constraint function based on speed limit, lane number and edge priority to compute traveltimes and flows based on density.
For details, see
src/marouter/ROMAAssignments::capacityConstraintFunction
src/marouter/ROMAAssignments::getCapacity

MAROUTER reads OD matrices and creates route files. These route files contain route distributions between traffic assignment zones. Each route in the distribution is a fully specified list of network edges.

regards,
Jakob

Am Mo., 10. Dez. 2018 um 00:29 Uhr schrieb Michał Lis <johny1614@xxxxxxxxx>:
Hi. I need to use macroscopic traffic flow model - it is necessary for some mathematical calculations. I have read in FAQ that sumo supports "macroscopic traffic assignment" using MAROUTER. I feel like this doesn't mean that I have full macroscopic model with elements like density, flow based on density etc. Am I right? After proceeding everything from documentation with MAROUTER I get traffic assignment zones, is this the point of  "macroscopic traffic assignment" support?
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