Amends GS 20-146 to require any vehicle on a controlled-access or partially controlled access highway to drive in a lane other than the inside lane next to the centerline or median when traveling at less than the speed limit or when impeding the steady flow of traffic (defined as when the person knows or reasonably should know that he or she is being overtaken from the rear by a vehicle traveling at a higher rate of speed). Includes exceptions for overtaking and passing another vehicle or when making a left turn. Violations are an infraction punishable by a $200 fine. Makes conforming changes. Applies to offenses committed on or after December 1, 2017.