Final answer:
The sole reason to stop or park on a highway shoulder is for emergencies only, such as mechanical failure or a medical emergency.
Step-by-step explanation:
The only reason you can stop or park on the shoulder of the highway is for emergency situations only. This includes situations such as mechanical failure, medical emergency, or some other situation where stopping is absolutely necessary to ensure the safety of all road users. While certain scenarios, like a pregnant woman about to give birth, could justify to some the breaking of a traffic law under the utility principle, it is always best to adhere to traffic laws for safety unless an exceptional circumstance mandates otherwise. Stopping on the highway shoulder for non-emergency purposes can cause safety hazards, obstruct traffic, and is typically illegal. The contexts provided, such as tollbooth wires or traffic signals, highlight the importance of road safety features in managing vehicle flow and ensuring the well-being of travelers.