Region in compliance with Clean Air Act


TriMet/Metro News Release

The Portland region is fully in compliance with Clean Air Act requirements and has been since 1996. A recent news release from OPAL incorrectly claimed the region is currently out of compliance due to transit service cuts during the recession.

The issue of clean air and compliance was discussed at the June regional JPACT (Joint Policy Advisory Committee on Transportation) meeting. The Department of Environmental Quality and Metro are proposing to change how the region calculates the region’s compliance with the Clean Air Act requirements related to transit service. The proposed change would continue to call for 1 percent annual transit service expansions, but look at a longer timeframe than the current rolling five-year window. The rolling five-year average timeframe was established in 2007. Since then, TriMet has increased transit service more than 1 percent each year weighted by capacity. However, service cuts in Fiscal Year 2011 due to the recession and the agency’s unsustainable benefit cost structure would lead to a future dip below the 1 percent requirement under the current rolling five-year window.  Moving to a long-term view does not impact the required transit growth rate, but allows the region to remain in compliance.

We share the same goal with OPAL, which is to restore and expand service as soon as it’s financially feasible. More transit service and transit trips results in fewer vehicles on the road and cleaner air. As we continue to work to realign our cost structure through contract reform and emerge from the recession, our first priority is to expand transit service.  

Background on the Clean Air Act requirements
The region is in the last four years of a Carbon Monoxide (CO) Maintenance Plan required by the Environmental Protection Agency (EPA) due to emissions of CO that exceeded limits during 1978 – 1995. Since 1996 the region has not come close to violating the CO standard and has demonstrated compliance for the past 15 years. But the maintenance plan must continue until 2017. 

As part of the CO Maintenance Plan, the region must meet Transportation Control Measures (TCMs) that include active transportation investments for biking, walking and transit. The TCM calls for a 1 percent increase in transit service weighted by capacity on a rolling 5-year average. The region has demonstrated with the transit TCM that it has met the 1 percent annual average increase in transit service using the established 5-year rolling average method. The current maintenance period started in 2007. For example, from 2007-2011 the annual average increase in transit service was 1.25 percent. From 2008-2012 the annual average increase in transit service was 1.18 percent.

Proposed change to Transportation Control Measures
Metro, the Oregon Department of Environmental Quality and TriMet are working with the Environmental Protection Agency to update the way the TCM is calculated to ensure the region does not fall out of compliance with Clean Air Act requirements.

If the current way of calculating the TCM continued through until 2017, it is projected that future years would fall out of compliance. Despite growth in service every other year from 2007 on, due to a drop in service in fiscal year 2011 caused by the economic recession, the rolling 5-year average going forward would likely dip below 1 percent. 

With the existing TCM, the region is only taking credit for air quality benefits during a rolling five year window. This does not show the long-term air quality benefits seen by continual investments in expanding the region’s transit network. The proposed substitution better accounts for the long term.

The proposal is to modify the TCM to require 1 percent or more average transit growth during the entire current maintenance period from 2007 – 2017, rather than just during any given 5-year portion. 

The region has been successful encouraging travel by modes that reduce total VMT (vehicle miles traveled) on the roads with tools including the TCMs, which in turn, reduce total CO emissions. 

VMT per person in the region started a general downward trend in 1997, has dropped every year since 2007 and is now lower than it has been at any time since 1990. (

Next steps
The TCM substitution process is set to be considered by DEQ this summer and JPACT and Metro Council this fall.