What conveys a driver's intent to change lanes?

Answer: B — Proper use of turn signals

The proper use of turn signals is the primary way to convey a driver's intent to change lanes. Turn signals are designed specifically for this purpose, allowing drivers to communicate their intentions to other road users well in advance of making a lane change. This communication is vital for road safety, as it helps ensure that other drivers and pedestrians are aware of what the signaling driver plans to do, allowing them to react appropriately. In contrast, using brake lights primarily indicates the driver is slowing down or stopping, while honking the horn is generally used as a warning or to grab someone's attention rather than to indicate lane changes specifically. Maintaining a steady speed does not communicate any intent to change lanes at all. Therefore, the correct way for a driver to show that they are preparing to change lanes is through the proper use of turn signals.