Reducing Greenhouse Gas Emissions from Transportation

The Air Pollution Control Division will be proposing a transportation rule package to reduce greenhouse gas (GHG) emissions and other air pollutants from transportation in Colorado. This rule is part of an ambitious effort to address climate change and meet the state’s science-based climate targets of 26% by 2025, 50% by 2030% and 90% by 2050 from 2005 levels, outlined in the state
Greenhouse Gas Pollution Reduction Roadmap.


Stakeholder Engagement Process

State staff would like to thank everyone (over 1,200 people) who participated in the stakeholder process since January 2021. The Division hosted five large public listening sessions (offered in English and Spanish), six listening sessions on the Employee Traffic Reduction Program, two workshops on equity considerations, and numerous small meetings with chambers of commerce, environmental groups, local governments, and community members.

Find out how to participate in the rulemaking process at the Air Quality Control Commission website.

To stay updated on the upcoming rulemaking process, please make sure you're signed up for Air Quality Control Commission (AQCC) notices by emailing your contact information to Subject: Email Distribution List.


Descubra cómo participar en el proceso de elaboración de normas en el sitio web de la Comisión de Control de Calidad del Aire.

Para mantenerse actualizado sobre el próximo proceso de elaboración de reglas, asegúrese de estar suscrito a los avisos de la Comisión de Control de Calidad del Aire (AQCC) enviando un correo electrónico con su información de contacto a Asunto: Email Distribution List

Main Rule Components

Employee Traffic Reduction Program (ETRP)

Due to concerns among some of the business community, the Division is now advocating that ETRP be entirely voluntary and ETRP will not go before the Air Quality Control Commission for a rulemaking hearing in August. You can view the official Notice of Withdrawal of the ETRP Proposal on the AQCC website.

We want to thank all of the parties to this rulemaking for the time and energy they contributed, as well as each and every stakeholder who participated in our lengthy outreach and engagement process. Your input helped us better understand the potential challenges and opportunities in implementing ETRP programs and this input will support the success of voluntary efforts and future regulations.

Division staff also wants to take this time to recognize the significant contributions that the Regional Air Quality Council as well as the area Transportation Management Associations (TMAs) and Transportation Management Organizations (TMOs) have made to this effort over the past several months. We are sincerely grateful for these partnerships and look forward to continuing working together to promote the reduction in single occupancy vehicle commuting in Colorado. These efforts are critical to meeting the state's greenhouse gas emission reduction targets, addressing ozone, and providing other air quality benefits to the people of our beautiful state.

Specifically, we would like to thank the hard-working staff of the following organizations for all their contributions to this effort:

  • The Regional Air Quality Council (RAQC)
  • Commuting Solutions
  • Denver Regional Council of Governments
  • Boulder Transportation Connections
  • Smart Commute Metro North
  • Transportation Solutions
  • Downtown Denver Partnership TMA
  • Northeast Transportation Connections
  • West Corridor TMA
  • Denver South TMA
  • North Front Range Metropolitan Planning Organization
  • Pikes Peak Area Council of Governments


Vehicle Emission Inspection Program 

(Fact Sheet) (Información General)

The Division is also proposing updates to Colorado’s vehicle inspection program to make it more effective in protecting air quality in the state. More information on the Vehicle Emission Inspection Program is available here.

Greenhouse Gas Pollution Standard

(CDOT webpage)

The Greenhouse Gas Pollution Standard rule will be going before the Colorado Transportation Commission for consideration. Please visit the Colorado Department of Transportation (CDOT) website for more details.

Rulemaking Process

  • Rulemaking hearing before the Air Quality Control Commission (AQCC): August 18-20, 2021

  • To provide written comment or sign up for updates, please email: (due August 3, 2021)

For more information or to register to attend the rulemaking hearing, please visit the Air Quality Control Commission website: