Exit Gates

At the Jan. 9 delegates meeting, a woman said she had had trouble with the Village exit gate coming down as she went to pass through. It was explained that the exit gates are timed to allow TWO cars to pass through, and it was all in the timing. I don’t think the woman understood how this works, so I thought I would make a stab at it on the BLOG.

With the gate timed for two cars, the second right behind the first, the gate will remain constantly up so long as there is a steady flow of cars one right behind another. This is why. Picture two cars close to each other headed toward the gate. The first car slows down or stops until the gate goes up. The second car doesn’t have to pause, because it can go through on the first car’s triggering of the mechanism. As it passes through, though, the second car also triggers the mechanism, causing the gate to stay up, not only for its own passage but the next car's passage as well. The gate therefore stays up as long as the cars follow very closely on one another.

The problem comes when there is a gap between cars. Imagine a line of cars with a gap in the middle. Car 4 is in front of the gap. Now imagine an invisible car in the gap, which we will call Car 5. The invisible car is followed by the car in back of the gap. We will call it Car 6. When Car 4 goes through, the gate stays up for Car 5, the invisible car. But because Car 5 is invisible, it doesn’t trigger the mechanism to stay up for Car 6. Car 6 sees the gate remaining up for the invisible car and thinks it will remain up for it to pass through. But of course it does not.

Is this close to the right explanation? Has my invisible car only made the whole thing harder to understand?

Lanny