You want to pass on the left on a two-way road. When you get back into the right lane, what is the minimum distance that must still separate you from any oncoming vehicle?

Why

Before passing on the left, check that you can return to the right lane safely before any oncoming vehicle comes within 200 feet of you. If you cannot, you may not pass. The other two numbers are real, but they belong to other rules. 100 feet is the distance from a railroad crossing on a two-way road within which you may not pass at all. 500 feet is the visibility a U-turn needs: other drivers must be able to see your car from that far in either direction. The same passing list also forbids passing near a curve or hilltop you cannot see past, and when your lane has a solid yellow center line. The figure to keep in mind is 200 feet, the room that must still separate you from the oncoming car when you get back to your lane.