The Trump administration took its first step towards tighter pollution control on heavy-duty trucks and truck engines after US Environmental Protection Agency (EPA) Administrator Andrew Wheeler signed an advance notice of proposed rulemaking Monday.

In 2016 more than 20 organizations petitioned the EPA to develop more strict emission standards after the EPA projected that heavy-duty vehicles would continue to be the largest contributors to the mobile source of oxides of nitrogen emissions (NOx) through 2028. In December 2016 the EPA highlighted several potential components of future action, which included improving test procedures and test cycles, updating certification and in-use testing protocols, and creating incentives to encourage the transition to current- and next-generation cleaner technologies as soon as possible.

The EPA announced plans in November to update standards for NOx from highway heavy-duty vehicles through the Cleaner Trucks Initiative (CTI).

In the advance notice of proposed rulemaking signed Monday, the EPA stated that it intends the CTI to be “a holistic rethinking of emission standards and compliance.” The ultimate goal is to reduce in-use emissions. To do so, the EPA will consider and enable technological solutions while considering cost impacts. These regulations should incentivize early compliance and innovation, and there should be a coordinated 50-state program. The EPA will also try to actively engage with interested stakeholders.

The EPA will be soliciting pre-proposal comments on the CTI.