Network Change Guide Wishlist

[JoeJimFlood]

This discussion is for expressing desires for the Network Change scenario, including specifics on the scenario to test and what metrics to demonstrate the calculation of. It is proposed to implement a change to the transit network as that is a common contemporary travel model application. Suggestions from the April 7 consortium meeting included leveraging the transit scenario used in testing the initial EET implementation. Some proposed metrics to demonstrate the calculation of include:

• Tour mode share
• Travel times
• Jobs within a transit ride of a given time

Please submit any comments before the April 21 consortium meeting.

[sumitbindra]

Network Editing Scenario

Problem Statement

1. (TransLink preference) The addition of BRT service with 5-minute headways in the peak periods on a major arterial.

   • Which trip purposes show the strongest mode shift response?
   • What would be the time savings by trip mode and by purposes? How does reduction in travel time by mode impact mode shift for different trip purposes?
   • Are workers adjusting their work departure time based on availability of BRT services? (What if BRT services start at 4AM versus 7AM?)

2. If a new managed lane reduces peak travel time by 8 minutes for SOV users, does the model show induced demand in subsequent feedback iterations? How many iterations are needed before assignment and ActivitySim reach equilibrium?

Components Impacted (Edit based on modeling system for testing)

1. Mode Choice Response – Adding BRT or a managed lane should shift mode shares, but the question is whether the shift is reasonable and traceable. The guide should walk through how to read mode choice coefficients, how to calculate expected utility changes from the skim improvement, and how to sanity-check that the model's response is proportional to the level of service improvement.

2. Time of Day Choice – Network changes often have peak vs. off-peak implications that ripple into time-of-day choice. A managed lane that only operates during peak hours, for example, should be shifting some tours earlier or later. This is a subtle effect that senior modelers need to understand how to look for and explain to stakeholders.

3. Tour and Trip Assignment Feedback – Depending on whether the model runs with feedback iterations, a network improvement that reduces congestion can affect departure time and destination choice in subsequent iterations. The guide should address when feedback matters for a given scenario type and how many iterations are sufficient.

Outputs / Summary

1. Mode shift by trip purpose
2. Departure time impact
3. Congestion impact

[JoeJimFlood]

There's actually a BRT project in the SANDAG regional plan that I was thinking about suggesting using (it connects the suburb I lived in with a couple neighborhoods I probably would have gone to more had the line existed).

[xiex0055]

It is easy to set up the model to simulate the long-term travel effects of a permenant network change (e.g., the permenant closure of a river-crossing bridge). However, is there any guideline regarding how to set up the ActivitySim models to simulate the short-term effects of a temporary network change (e.g., the temporary closure of a river-crossing bridge for renovation)? Similar to the set-up in a trip-based model, we may want to freeze the long-term choices (e.g., workplace location, car ownership) and work related choices in such a scenario.