The leader of the Knights of Labor in 1879 is Terence V. Powderly.
Answer: Traffic counter
Explanation: The traffic counter device is usually employed in taking accurate count or record of cars plying a particular road. They are usually electronic in nature which takes readings of vehicles, usually in the scenario above, which involves a just taking temporary count in other to make decision on whether to install a traffic light system or not, a pneumatic tube is usually employed, which are large black cables laid along the highway, the usually pressure filled such that when a vehicle passes across, it takes a count.
The answer is post hoc. This is a logical fallacy that states "after this, therefore because of this." This fallacy is used when one is coming to a conclusion based on an order of events rather than using other factors that might lead to other interpretations.