[sumo-user] Dfrouter makes vehicle routes not ending at detectors

[Pieter L. <lo...@gm...>]

Hello,

I'm trying to simulate a simple highway scenario based on detector
measurements using dfrouter. I have a highway piece in two directions with
halfway an on-ramp and off-ramp for both directions. Detectors are located
on the highway before, in between and after the two ramps for each driving
direction. I found out that a significant amount of vehicles leave the
highway at the off-ramps, which causes the number of vehicles that is
measured at downstream detectors to be far too low.

I was expecting that dfrouter only computes routes between source and sink
detectors, but apparently it also adds routes that do not end at sink
detectors. Is there a way to have dfrouter only compute routes that end at
sink detectors? I don't like it that dfrouter exits a lot of vehicles
prematurely without me having any control over it.

So if there's a simple fix, please advise me. I can come up with some
solutions that are not really pleasing because they are not neat and
require more time:
1. Add dummy sink detectors at off-ramps that measure 0 cars. I wonder
whether this would actually work.
2. List all off-ramp edges and give them to dfrouter with
option "--disallowed-edges".

Best regards,
Pieter