Which of the following is a proper action when you see brake lights in front of you?

When you see brake lights in front of you, it indicates that the vehicles ahead are slowing down or coming to a stop. In this situation, the appropriate response is to slow down and prepare to stop. This action ensures you maintain a safe following distance and minimizes the risk of a rear-end collision.

In addition, slowing down allows you to assess the situation ahead and react accordingly, whether that means stopping completely or proceeding once it is safe. It's essential to be aware of the behavior of other vehicles on the road and adjust your driving accordingly to maintain safety for yourself and other drivers.

Maintaining your speed in the presence of brake lights would be unsafe, as it does not account for the potential need to stop suddenly. Accelerating to change lanes can create hazards if the vehicle in front stops, and using your horn may cause confusion or panic without addressing the immediate need to slow down.