When a large black cable is laid across a street to count the number of cars that travel along that street in an attempt to use the information to decide whether or not to install a traffic light at the next intersection this is an example of:.

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.