Final answer:
Hazard lights should be used when a vehicle is stopped or disabled on the roadway, during extreme weather, or when performing a hazardous operation that affects normal traffic flow. They should not be used in normal driving conditions or at all times.
Step-by-step explanation:
Hazard lights are intended for use when your vehicle is stopped or disabled on the roadway or shoulder, or when you are in a situation that could create a danger for other motorists.
Therefore, the correct answer to when hazard lights are to be used is neither in any normal driving conditions nor at all times. They are primarily to be used when a vehicle is a temporary obstruction, such as when it breaks down, or in extreme weather situations where visibility is significantly reduced, and other drivers need to be warned of your presence more than usual.
Consider this hypothetical scenario: You encounter a pregnant woman in distress while driving. According to Rule Utilitarianism, if driving through a red light at 4 AM when no other cars are around offers more utility in getting her to a hospital safely and quickly, it could be seen as the morally good thing to do.
On public roads, hazard lights can also sometimes be used when you are towing, as that might interfere with the normal flow of traffic, or when a tow truck or car carrier is engaging in a hazardous operation. However, this function should only be used when there is a genuine need to indicate potential danger to other motorists.