House committee substitute to the 1st edition makes the following changes.

Amends GS 20-141(c) to add minimum operating speeds of 55 mph in a 65 mph speed zone, and 60 mph in a 70 mph speed zone. Directs the Department of Transportation to post replacement signs indicating the new minimum speeds where signs are posted with the previous minimum operating speeds.

Adds an exception from the prohibition on trucks operating in the left lane for trucks entering or exiting a highway to the proposed subsection (f) in GS 20-146.

Clarifies that Sections 1 through 3 of the bill (concerning Impeding Traffic, Minimum Operating Speeds, and Trucks in Left Lane) are effective December 1, 2025.