In what circumstance is displacement the same as distance traveled?

They have the same magnitude when the travel is in a straight line with no curves or back-ups.

Usually when you travel in a straight line, or one direction. The difference is that if you drive 10 feet in one direction, you are 10 feet from where you started. If you drive 10 feet forward, then 10 feet backward, you are in the same place you started, so you displaced yourself 0 feet. But, you travelled 10 ft + 10 ft, so your distance travelled is 20 ft.