Which of the following actions is recommended if you suspect someone is driving under the influence?

If you suspect someone is driving under the influence, calling law enforcement is the recommended action because it ensures that trained professionals can assess the situation and intervene appropriately. Law enforcement has the expertise and legal authority to handle suspected cases of impaired driving, which can involve safely pulling the driver over to evaluate their condition. This can prevent potentially dangerous situations on the road, such as accidents that could harm the driver, passengers, or other roadway users.

Acting in this way is also crucial for safety, as you may not know how the impaired driver might react to confrontation. Observing from a distance, rather than following closely, can provide information to law enforcement without escalating the situation or putting yourself at risk. Ignoring the situation fails to take proactive measures to protect others, and confronting the driver directly may provoke them or lead to a confrontation that could be hazardous.