Re: [sumo-user] Measuring Capacity of a Lane

["Bae, Jong In" <jbae42@xxxxxxxxxx>]

Jakob,

I must be doing something wrong. I changed the simulation step length to 1s and re-ran the experiment.

The maximum hourly vehicle count was still around 1,040 vehicles/hr.

Did you still get the flow ~880 when you ran a test with my scenario?

I wonder if I am using a different methodology or setting than you are.

I think it'd be better to first get the same result as you and then start exploring the effects of using different settings.

Thank you so much for your help!

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From: sumo-user-bounces@xxxxxxxxxxx <sumo-user-bounces@xxxxxxxxxxx> on behalf of Jakob Erdmann <namdre.sumo@xxxxxxxxx>
Sent: Monday, September 14, 2020 10:01 AM
To: Sumo project User discussions <sumo-user@xxxxxxxxxxx>
Subject: Re: [sumo-user] Measuring Capacity of a Lane

 

Hello,

the difference in observed flows comes from the different step-lengths of the simulation. An explanation is given at https://sumo.dlr.de/docs/Car-Following-Models.html#actionsteplength

Basically, the effect on reaction time affects the flow when starting a queue of stopped vehicles.

regards,

Jakob

Am Fr., 11. Sept. 2020 um 18:14 Uhr schrieb Bae, Jong In <jbae42@xxxxxxxxxx>:

Jakob,

Thank you for your reply and taking a look at my scenario.

Please see the attached zip file for the scenario files.

I've also attached the results I got from the e3Detectors where I summed up the 'interval_vehicleSum' (the last 3600s) for the capacity.

Thank you,

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From: sumo-user-bounces@xxxxxxxxxxx <sumo-user-bounces@xxxxxxxxxxx> on behalf of Jakob Erdmann <namdre.sumo@xxxxxxxxx>
Sent: Friday, September 11, 2020 3:34 AM
To: Sumo project User discussions <sumo-user@xxxxxxxxxxx>
Subject: Re: [sumo-user] Measuring Capacity of a Lane

 

Hello,

my own test shows a flow of ~880.

If the road after the signal continues at 14m/s, flow drops to 780

If there is a turn after the signal, flow drops even further depending on turning radius.

Can you share your scenario?

regards,

Jakob

Am Do., 10. Sept. 2020 um 19:23 Uhr schrieb Bae, Jong In <jbae42@xxxxxxxxxx>:

Hello,

I ran a simple experiment to measure the capacity of a one-lane signalized exit ramp that is 1500 feet long.

The result came out a lot higher than expected. The capacity came out to be roughly 1,100 veh/hr. (I was expecting to see around 750~800 veh/hr since the ramp is signalized). 

Is this a typical capacity value in SUMO? I've also included a brief scenario settings and methodology below.

The goal was to measure the capacity of a one-lane exit ramp which is 1500 feet long.

A signal (G:50, R:70) is placed at the end of the exit ramp. A single vehicle type was used with minGap=2.2 and tau=1. 

The speed on the exit ramp is 24.59m/s (approximately 55mph). A few iterations were done with various traffic flows.

Each iteration was run for 4500 timesteps where the vehicle count of the last 3600 timesteps was collected (first 900 timesteps were a warm-up period).

e3detectors were placed right after the signal and 'vehicleSum' was used to get the vehicle count for the 3600 timesteps.

The maximum count out of all iterations was determined to be the capacity.

Any help would be greatly appreciated.

Thank you,

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Attachment: capacity.zip
Description: capacity.zip