Colorado Adopts Advanced Clean Trucks and NOx Rules

In April 2023, Colorado adopted Advanced Clean Trucks (ACT) and Low-Nitrogen Oxides (Low-NOx) rules, adding their name to the list of states following California’s model. Under the ACT rules, beginning in 2027, manufacturers must make more zero-emission trucks available in Colorado, based on a percentage of sales that increases through model year 2035. The Low-NOx rule sets more stringent air pollution emissions standards for heavy-duty vehicles, and will reduce nitrogen oxide emissions for new vehicles by 90 percent compared to the current standard.