Re: [sumo-user] A question about timestep and tau

[Jakob Erdmann <namdre.sumo@xxxxxxxxxxxxxx>]

Did you install version 0.32.0 or did you use the latest development version from here: http://sumo.dlr.de/wiki/Downloads#SUMO_-_Latest_Development_Version ?

You can obtain queue-length using the lanearea detector: http://sumo.dlr.de/wiki/Simulation/Output/Lanearea_Detectors_(E2)

A good measure of congestion is time loss. A global value can be obtained by activating the statistics output: http://sumo.dlr.de/wiki/Simulation/Output#Aggregated_Traffic_Measures

regards,

Jakob

2018-04-11 19:33 GMT+02:00 Rahimi, Tariq Rahim <TariqRahim.Rahimi@xxxxxxxxxxxxxxxxxxx>:

I appreciate your response,

I installed the newer version just yesterday and I am still getting waitSteps in the Tripinfo output and I don't get any waitingTime.

Additionally, where can I get a good measure of queue length and congestion?

Thank you,

-------------------------------------
Tariq R Rahimi

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From: Jakob Erdmann <namdre.sumo@xxxxxxxxxxxxxx>
Sent: Tuesday, April 10, 2018 3:00:19 AM
To: Rahimi, Tariq Rahim
Cc: Sumo project User discussions
Subject: Re: A question about timestep and tau

 

Hello,

The value of waitSteps counts the number of simulation steps in which a vehicle was waiting. So if your vehicle waits for 3 seconds and you simulation with --step-length 0.2 that would be 15 waitSteps.

In the latest development version, the attribute waitSteps is replaced with waitingTime which is measured in seconds. (http://sumo.dlr.de/wiki/ChangeLog#Git_master).

The value of tau determines the desired time-headway between successive vehicles. The exact usage of this value depends on the car following model (see http://sumo.dlr.de/wiki/Definition_of_Vehicles,_Vehicle_Types,_and_Routes#Car-Following_Models)

To model different perception-reaction times, see http://sumo.dlr.de/wiki/Car-Following-Models#Model_Parameters

regards,

Jakob

2018-04-10 2:50 GMT+02:00 Rahimi, Tariq Rahim <TariqRahim.Rahimi@rockets.utoledo.edu>:

Hello everyone,

When I output the tripinfo, it says waitSteps= an integer value. How can I get this or the total waiting time for each vehicle in seconds? Also, how can I calculate a queue length?

What is the concept of time Step? when I generate a route file with 12 vehicles departing at the same time step but in different time frame, such as the first vehicle departs at 0 seconds, the second at 3rd second, the third one in 6th second but they all are departing at the same time step. Here, the time step in 9 seconds. 10 minutes later, there are 5 vehicles departing at the same time step and the time step there becomes 5 seconds.

What can I make of time step if I want to calculate the waiting time at an intersection?

Also, any ideas on what does tau trigger? what file can I find it's source code and what functions are related to it? I want to simulate different perception-reaction times (0.5 second, 1 second, 2 seconds), How should I go for it?

Thank you,

-------------------------------------
Tariq R Rahimi

Graduate Student