Re: [sumo-user] JTR router with fixed turning ratios

["Tilg, Gabriel" <gabriel.tilg@xxxxxx>]

Hello Jakob,

 

first of all – thanks for the helpful reply!

 

While I continued to work with the JTR router and the routeSampler tool, several questions came up and I would be very happy for any further help:

 

JTR router

-       Does it make sense to define smaller interval sizes, but do not change the turning ratios in these intervals?

-       What’s the effect of “route-steps”? Does it only affect the result when different turning ratios are specified for different interval sizes?

 

RouteSampler

When I apply the RouteSampler.py, I indeed get more uniformly distributed turning flows. As input, I take the routes previously computed by the JTR router. However, the overall desired accumulated counts are not correct. I confirmed this by applying the “generateTurnRatios.py”. For example, at a specific intersection (two unidirectional links crossing) the turning ratios should be 50% for each leg. In contrast, I got 47% and 53% after applying the routeSampler. I apply the “—optimize full” option, and the interval size does not seem to have a big impact.

 

-       Does it make sense to reduce the counts for early intervals at intersections where it takes some time to load the network?

-       Are there any other ways to reach the desired turning ratios?

 

Thank you very much for any help!

 

Best

Gabriel

 

 

Von: sumo-user-bounces@xxxxxxxxxxx [mailto:sumo-user-bounces@xxxxxxxxxxx] Im Auftrag von Jakob Erdmann
Gesendet: Dienstag, 28. April 2020 23:32
An: Sumo project User discussions <sumo-user@xxxxxxxxxxx>
Betreff: Re: [sumo-user] JTR router with fixed turning ratios

 

Hello,

in general, you cannot remove the dependency on traffic states (if there is an upstream jam on some approaches, vehicles will inevitably be delayed).

Also, jtrrouter does not offer options for reducing randomness due to sampling from the turn-ratio distribution.

 

As an alternative, you could use turning count data with the routeSampler tool. This will give you exact counts within the specified time intervals.

By varying the size of the time interval you can influence the maximum deviation from the desired ratios (i.e. 50 in 100 vehicles turning right or 5 in every 10 vehicles turning right). See https://sumo.dlr.de/docs/Tools/Turns.html#routesamplerpy

 

regards,

Jakob

 

 

Am Di., 28. Apr. 2020 um 18:06 Uhr schrieb Tilg, Gabriel <gabriel.tilg@xxxxxx>:

Hello all,

 

I am aiming to use the JTR router in order to route flows according to turning ratios. I noticed that the actual turning ratios are dependent of traffic states and include stochasticity.

 

For example, I created a network (~24 nodes), created some origins (~10), and defined the turning ratios. They are either 100, 50 or 25%. So, I was expecting every second or fourth vehicle to turn, but apparently the turning movements are not that deterministic. Additionally, there seems to exist a relation to congestion.

 

Is there a way to reduce both the dependency on traffic states, and the stochasticity?

 

Thank you very much in advance!

 

Best regards,

Gabriel

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