Simulating highway/freeway/expressway

[emcnichols]

Hi! I'm trying to simulate a section of a US interstate highway with 6 travel lanes during rush hour. When I use a bottle neck node, the traffic indeed slows down but too much and there are also less vehicles per time step than expected.

How can I go about correctly simulating this scenario?

[toruseo]

Hi, thanks for using UXsim!

There are several ways to represent a highway bottleneck.

1. Use the capacity_out argument of Link

You can set the traffic capacity of a link (i.e., the maximum flow rate of traffic that exit the link) using World.addLink(..., capacity_out=0.7*6).
Adjust the capacity_out value to get the behavior you want.
The unit of capacity_out is vehicles per second, and the default value (without a bottleneck) is 0.8 vehicle/s/lane.

2. Use the flow_capacity argument of Node

Alternatively, you can set the traffic capacity of a node (i.e., the maximum flow rate of traffic that pass the node) with World.addNode(..., flow_capacity=0.7*6).
Note that this capacity limits every traffic that pass the node. If the node is shared by traffic for both highway directions, you need to set corresponding capacity.

Pls let me know if you have further questions.