What should you do when traveling below 40 mph on a limited access highway?

When traveling below 40 mph on a limited access highway, using your four-way flashers is the appropriate action to ensure the safety of yourself and others. Limited access highways are designed for higher-speed travel, and driving significantly slower than the flow of traffic can create a hazard for other drivers who may not expect slower vehicles. Activating your four-way flashers alerts other motorists to your presence and indicates that you are moving more slowly than typical highway speeds. This can help prevent accidents by providing a visual warning that enables drivers approaching your vehicle to respond appropriately.

While using headlights can enhance visibility, it doesn't specifically convey the message of slower speed in the same immediate way that four-way flashers do. Honking your horn is generally not a recommended response in this situation, as it can be misinterpreted and doesn't serve as a warning to other drivers about your slower speed. Braking gently could be appropriate if you're trying to reduce speed, but it's not a proactive measure to communicate your reduced speed to other drivers on the highway. Thus, the use of four-way flashers is the most effective and safe choice in this context.