Which of the following is a time you should NOT use cruise control?

Using cruise control on a winding, single-track road is not advisable due to the need for constant speed adjustments that such driving conditions require. These roads often feature sharp curves and elevation changes that demand quick reactions and precise handling. When driving in these environments, it is critical to maintain full control over acceleration and braking to maneuver through turns safely and respond to any unexpected obstacles.

The other contexts provided, such as driving on a freeway or during low-density traffic on a rural road, generally allow for more steady speeds, making cruise control a viable option. A bright sunny day on the Coquihalla Highway, although presenting good visibility, does not negate the potential hazards of the road's terrain and traffic conditions. Therefore, utilizing cruise control in areas where active and responsive driving is essential, such as winding roads, is not appropriate or safe.