* Sitting still. When you are sitting still, you are not moving, so your speed is zero.

* Walking slowly. When you are walking slowly, you are moving, but your speed is still relatively low.

* Driving in heavy traffic. When you are driving in heavy traffic, you are often moving slowly, even if you are trying to go faster.

* Stopped at a red light. When you are stopped at a red light, you are not moving, so your speed is zero.

* Asleep. When you are asleep, you are not moving, so your speed is zero.