Difference Between Advisory Speed Signs and Regulatory Speed Signs
"Regulatory signs shall be used to inform road users of selected traffic laws or regulations and indicate the applicability of the legal requirements."
Regulatory speed signs designate the maximum speed drivers should travel at in good driving conditions. If this speed is violated, drivers can be ticketed by law enforcement. Regulatory speed signs do not usually designate the reason for the speed limit.
"Warning signs call attention to unexpected conditions on or adjacent to a highway or street and to situations that might not be readily apparent to road users. Warning signs alert road users to conditions that might call for a reduction of speed or an action in the interest of safety and efficient traffic operations."
Advisory speed signs are used in conjunction with another warning sign such as a curve ahead sign or a narrow road sign. The advisory speed lets the driver know of a safe speed to travel, given the conditions of the road and environment surrounding the road.