Which of the following indicates an impending seizure while driving?

The presence of sudden loss of consciousness or unusual body movements is a clear indicator of an impending seizure while driving. Seizures can manifest in dramatic ways, often involving alterations in awareness or bodily control. If a driver experiences these symptoms, it can severely impair their ability to operate a vehicle safely, leading to dangerous situations on the road.

Sudden loss of consciousness could result in the driver becoming unresponsive, while unusual body movements may indicate a convulsive seizure. Both situations would likely lead to an immediate need to take action, either by pulling over safely or alerting other drivers to the potential for an accident.

In contrast, sudden acceleration, a flashing dashboard light, or an increase in speed may relate to vehicle mechanical issues or driver error but do not specifically signal a neurological event like a seizure. While these might point to other problems that also require attention, they do not indicate an imminent seizure, which is more specifically characterized by the symptoms outlined in the correct answer.