When encountering a speeding, erratically driving car that isn't signaling, what should the driver do?

Reducing speed in response to a speeding and erratically driving car is a prudent and defensive action. When a driver observes another vehicle behaving unpredictably, such as speeding and not using signals, it is essential to create more space and time to react safely. By lowering speed, the driver can better assess the situation and potentially avoid a collision.

This action also reduces the likelihood of exacerbating the situation, as accelerating or changing lanes might provoke further erratic behavior from the other driver or make it harder to avoid an accident should the need arise. Remaining calm and composed while giving oneself extra room to maneuver is a fundamental aspect of defensive driving and promotes a safer roadway for everyone involved.

The other options involve actions that could lead to dangerous situations. For instance, speeding up to get ahead might provoke a dangerous response from the erratic driver or lead to a loss of control. Changing lanes without signaling lacks the communication that is necessary on the road and could lead to confusion or crashes. Sounding the horn may alert the other driver, but it doesn't inherently solve the problem or contribute to the driver's safety in that moment.