Which of the following actions constitutes a violation of the Transportation Code?

The action of a vehicle slowing down but not coming to a complete stop at a stop sign constitutes a violation of the Transportation Code because the law mandates a full stop at all stop signs. This requirement is in place to ensure safety at intersections, where failing to stop completely can lead to accidents involving other vehicles or pedestrians. The law is designed to prevent misunderstandings about right-of-way and to promote cautious driving behaviors in areas where visibility may be limited or where other road users might be present.

The other choices represent actions that comply with the Transportation Code. Coming to a full stop at a red light is legally required, yielding to pedestrians in a crosswalk is essential for pedestrian safety, and maintaining the speed limit ensures adherence to safe driving practices. Each of these actions aligns with the regulations set forth to promote safe driving behavior on the road, making them valid and acceptable under the law.