NHTSA Issues New Underride Guard Rules - Heavy Duty Trucking
NHTSA has issued new underride guard rules, requiring stronger rear impact guards on trailers and potentially side guards, to reduce fatalities in crashes. Compliance deadlines are phased in over the next few years.
Aforeworn detected this change in the Trucking / FMCSA Compliance space on July 6, 2026 and published this briefing so affected operators are forewarned rather than caught off guard. It is rated Medium urgency. Motor carriers operating trailers with a GVWR over 10,000 lbs, especially those with older trailers. should confirm how it applies to their specific situation before acting. There is a time constraint attached: Phase-in begins 2025 for rear guards; side guard rule effective 2027.. Acting after that point can mean penalties, a lapsed licence, or lost eligibility — exactly the kind of surprise Aforeworn exists to prevent. Aforeworn monitors Trucking / FMCSA Compliance continuously and turns every detected change into a plain-English briefing like this one, so you always know first. Forewarned is forearmed.
What changed
New FMVSS 223/224 requirements for rear underride guards, and a new FMVSS for side underride guards on certain trailers.
Who it affects
Motor carriers operating trailers with a GVWR over 10,000 lbs, especially those with older trailers.
What you must do
Ensure all trailers in fleet meet new guard standards by the compliance deadline; retrofit or replace non-compliant trailers.
Deadline
Phase-in begins 2025 for rear guards; side guard rule effective 2027.
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