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Re: [sumo-user] Validation of BPR Method in SUMO: Seeking Help on Replicating Asymptotic Results in Straight Road Sections

Dear François,

 

as you already noted, travel times on inflow edges depend a lot on the insertion rules and the used car-following settings. The next vehicle to be inserted needs some space (vehicle length and distance to leader) and only one vehicle per time step and lane can enter the network. To some extent, your question is similar to "how to replicate the fundamental diagram in sumo" (especially the saturated part). You need some way to increase the vehicle density which will lead to longer travel times.

 

Either create an artificial bottleneck or let vehicles circulate in the network for longer and keep some distance from inflow places when measuring the travel time.

 

Best regards

Mirko

 

 

 

-----Original-Nachricht-----

Betreff: [sumo-user] Validation of BPR Method in SUMO: Seeking Help on Replicating Asymptotic Results in Straight Road Sections

Datum: 2024-01-15T08:29:15+0100

Von: "François Vaudrin via sumo-user" <sumo-user@xxxxxxxxxxx>

An: "Sumo project User discussions" <sumo-user@xxxxxxxxxxx>

 

 

 

Hello,

I'm seeking assistance in validating the BPR method using SUMO to express travel time based on road capacity. The Bureau of Public Roads (BPR) formula is commonly used to model travel time on a road as a function of its capacity: After reaching a certain flow threshold, travel time increases exponentially until reaching the ultimate capacity of the road.

 

where:

  • T is the travel time on the road,
  • Tff ​ is the initial travel time,
  • q is the flow of traffic (number of vehicles per unit time),
  • qpc is the capacity of the road (maximum number of vehicles the road can accommodate per unit time),
  • α and β are adjustable parameters.
Despite increasing the flow of vehicles in a network with SUMO, Vehicles are being pushed backward before entering the network, possibly due to a required distance (likely related to the car-following model), but the results are not the same than BPR. The Time Tff appears to be a straight line rather than an asymptotic curve.
 
Appreciating any insights or suggestions to obtain similar results of BPR?

 

Wishing a fantastic year ahead to the SUMO teams and contributors!

 

François Vaudrin
semaphor.ai
Québec city, Canada
 
 
 
 


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