The federal government is one step closer to a rule requiring side underride guards on trailers to mitigate underride crashes into the sides.

The National Highway Traffic Safety Administration recently sent an advance notice of proposed rulemaking (ANPRM) on side underride guards to the White House Office of Management and Budget. OMB must approve it before it’s published in the Federal Register. An ANPRM, or "pre-rule," is a notice primarily intended to request information and data before developing a proposed rule.

This rulemaking would respond, in part, to a Sept. 12, 2013, petition for rulemaking from Ms. Karth and the Truck Safety Coalition to start studies and rulemakings on side guards and front override guards on trucks. It's also a response to a provision in the Bipartisan Infrastructure Law.

Last summer, NHTSA issued a final rule for rear underride protection and said it was implementing a number of other underride provisions of the Bipartisan Infrastructure Law, including: 

• Establishing a Federal advisory committee on underride protection, which will complete research on side underride guards for trailers and semi-trailers to assess their effectiveness, feasibility, benefits, costs, and impact on intermodal operations.

• Planning to publish an advance notice of proposed rulemaking to consider requirements for side underride guards for crashes into the sides of  trailers and semi-trailers. This rulemaking also responds to a provision in the Bipartisan Infrastructure Law to report the findings of research on side underride guards in a Federal Register notice to seek public comment.

Bills that would require side underride guards have been introduced in at least the last three congressional sessions, in 2017, 2019, and 2021, but did not make it into law.

In 2017, the Insurance Institute for Highway Safety demonstrated the potential benefit of placing side underride guards on trailers, comparing crash data on trailers with and without side underride guards in collisions with passenger sedans at 35 mph. It found that passengers were more likely to sustain fatal injuries when hitting a trailer without the guard. One test evaluated the AngelWing side underride protection device from Airflow Deflector, while a second test was on a trailer with only a fiberglass side skirt.