In what situation should a driver use the four-way flashers?

Using four-way flashers is an important safety measure for drivers in specific situations. The correct scenario for activating them is when experiencing vehicle trouble or making a roadside stop. This alert mechanism signals other drivers that your vehicle is not moving or is experiencing an issue, thus enhancing safety on the road.

When your vehicle is disabled or you're pulling over due to an emergency, turning on the four-way flashers makes your vehicle more visible to other drivers, helping to prevent accidents and ensuring that they understand there may be a potential hazard ahead. This is particularly crucial on busy roads where a stationary vehicle could be at risk of being hit.

In contrast, while stopping on a street might seem like a valid use for flashers, simple stopping doesn't inherently indicate a hazard, and using flashers in a no-parking zone does not communicate an urgent need for caution. Similarly, while driving in a parade may involve low speeds and increased visibility, it is not typically a situation where four-way flashers are necessary, as the context is controlled and well-communicated by the event organizers. Thus, utilizing four-way flashers in the case of vehicle trouble is the most appropriate and safest usage.