[NEWyear]

I think the simpiliest solution is to have two switches to work the light. One switch controlled by a man monitoring the pit stop itself, and another watching for traffic. The driver would only get the green light when both switches have been tripped.

I think they have 3 of them switches. I for a guy monitoring the tire changes, one for monitoring the fuel guys and one for the pit lane traffic. Still they got it wrong. Because it's 3x more decision making processes and thus 3x more chances for an error to appear.