Re: [sumo-user] Variable traffic flows, density and arrival times

[Hriday Sanghvi <sanghvih@xxxxxx>]

Follow up:

Here is a flow definition I am trying to imitate by TraCI insertions:

<flow arrivalLane="current" arrivalPosLat="center" begin="0" departLane="free" departPosLat="center" departSpeed="desired" id="flow_btt" number="6000" route="bottom_to_top" type="veh" vehsPerHour="6000" />

In TraCI:

for veh_id in range(1, 6000 + 1):
    agent_id = str(veh_id)
    traci.vehicle.add(
        agent_id,
        "bottom_to_top",
        "veh",
        depart=0,
        departLane="free",
        departPos="base",
        departSpeed="desired",
        arrivalLane="current",
        arrivalPos="max",
        arrivalSpeed="current",
    )

It's the exact same one, with all other configurations being the same. And yet, somehow there are differences in these statistics:

Predefined flow finished at step 7660, departDelay="2025.31", totalTravelTime="58439.00", totalDepartDelay="12151865.00".

TraCI imitation finished at step 8260, departDelay="4124.97", totalTravelTime="58424.00", totalDepartDelay="24749795.00"

Does a predefined flow in a routes file do something additional that the TraCI imitation by vehicle insertion is missing - I'm guessing it sets the times of insertions for each vehicle differently. Is it possible to equalize these behaviours or is this an impossible task?

Thank you,

Sincerely,

Hriday

On Sat, 6 Jan 2024 at 12:14, Hriday Sanghvi <sanghvih@xxxxxx> wrote:

Hello,

I was trying to implement dynamic flows where I wanted to change the vehsPerHour mid-simulation.

Example flow:
<flow arrivalLane="current" arrivalPosLat="center" begin="0" departLane="random" departPosLat="center" departSpeed="max" id="flow_btt" number="100" route="bottom_to_top" type="veh" vehsPerHour="6000" />

I couldn't find a way to dynamically set/update flows using TraCI, so I assume I have to add vehicles using TraCI to simulate a particular type of flow?

1. So if I wanted to insert vehicles at a rate of 6000 vehs/Hour, I need to insert 6000 / (60 x 60) = 1.6667 vehs/Second or 2 vehs/Second? (assuming 1 second = 1 TraCI simulationStep()?

2. There seem to be limitations to 1. For example, if there is a road with only a single lane, then there is a maximum vehicle flow that it can tolerate, beyond which there is no effect. Is that correct? So I would have to have multiple lanes to increase the flow?

3. Assuming 2 is correct, since 1 lane cannot have a flow higher than 1 vehs/Second, I will need as many lanes 'x' to accommodate the desired flow [x] vehs/Second? If not, then what are the other ways apart from increasing number of lanes that can increase the capacity of the road to tolerate more vehsPerHour or flow?

Please advise.

Thank you,

Sincerely,

Hriday