Comments: Visualize 2050 Draft Air Quality Conformity Scope of Work

To: TPB Board members, and Cristina Finch, TPB Planning Manager 
CC: Kanti Srikanth, TPB Director
From: Bill Pugh, AICP CTP 

The Coalition for Smarter Growth provides the following specific comments on the Visualize 2050 Air Quality Conformity scope of work. These comments supplement CSG’s prior comments on the Visualize 2050 Conformity Inputs submitted: 

  • March 20, 2024 comment letter to the TPB Board on Visualize 2050 
  • March 27, 2024 TPB Visualize 2050 Feedback Form responses

We recommend that the Air Quality Conformity process – following a review of projects that complies with board resolution R19-2021 – incorporate the following:

1. Show the extent of air pollutant improvements due to the change in the EPA model used versus changes in projects and travel inputs between Visualize 2045 and Visualize 2050

The February TPB Technical Committee briefing on the change in the air quality model to be used (going from EPA MOVES3 to the EPAMOVES4 model) showed that just the model change would result in notable changes in results for GHG, NOx, and VOCs. When TPB reports the results of its air quality conformity modeling, it will be important that TPB show the relative magnitude of changes due to the model assumptions versus due to changes in the transportation network and travel pattern assumptions.

The sensitivity analysis conducted by TBP staff on the new EPA MOVES4 model was very helpful, showing a decline in GHG results by as much as 20% in later years simply due to the change in the model. The declines in GHG and criteria pollutants due to updated fuel economy standards and other factors are good news. TPB staff will need to do a similar comparison of Visualize 2045 and 2050 results showing what is due to the model change. 

2. Clearly state the telecommuting and post-pandemic travel pattern assumptions and use the most recent data possible to inform these

Please communicate the telecommuting assumptions that will be used. Do these reflect current patterns?  It will be important to explain what has changed between Visualize 2045 and Visualize 2050 in these assumptions and how these compare with current day telecommuting and general travel patterns. 

3. Incorporate documented increases in non-work car trips for teleworkers in the modeling

Recent studies have shown that on average teleworkers add non-work trips for the work trips they don’t make. It is important that TPB’s modeling capture these additional non-work trips when accounting for telecommuting patterns in its air quality conformity analysis. 

The State Smart Transportation Initiative (SSTI) summarizes a key recent study:

The work confirms what other studies have found—that remote work can have an induced-travel effect on non-work trips. It found that people tend to make one extra trip on days they work from home. The researchers also determined it is typically a new trip, and not one that would have been taken another time. They note that this new trip is usually shorter than a commute, so the overall effect of remote work on total travel distance is negative. But they also warn, “the travel reduction effects of telecommuting will be overestimated if the new trip-generation is not taken into account.”… The researchers also add that the induced non-work travel caused by remote work could be even larger now that COVID concerns have dwindled. 

SSTI, February 27, 2024, Workers offset their commute travel when working from home, https://ssti.us/2024/02/27/workers-offset-their-commute-travel-when-working-from-home/

4. Show what levels of per capita VMT reduction will be needed to achieve the COG and TPB greenhouse gas reduction targets for 2030 and 2050 and how the package of projects performs relative to these

We know to meet the minimum COG target this is in the magnitude of a 20% light duty per capita VMT reduction by 2030 from pre-pandemic levels based on TPB’s Climate Change Mitigation Study of 2021 and other national studies. TPB needs to clearly state the per capita VMT reduction needed and analyze how the finalized package of projects would perform based on current electric vehicle adoption forecasts. 

5. Break down performance results by sub-areas (core, inner ring, outer ring)

Visualize 2045 only did this for a few metrics. A fuller technical appendix with these results would be helpful for jurisdictions to understand how their policies and projects affect regional outcomes – this was also a comment of a board member at the March TPB meeting.


We appreciate the lengthy time, effort and technical attention that staff spend on the air quality conformity modeling and hope these comments can help bring to light results and assumptions that are important for the public and board members. Thank you for the opportunity to comment.