Pneumatic Tube Counts are done by having a set of tubes installed across the pavement which collect data by the change in pneumatic (air) pressure to the receiver. As a car drives over the set of tubes a burst of air pressure is sent to a controller which translates this into an electrical signal which is transmitted to a controller that contains software that is able to convert the change in air pressure and calculates the speed and classification of a vehicle (or cyclist) who travelled over the tubes.
These counts are recording the number of vehicles, vehicle speed, and classification (car, truck, semi-truck, cyclist etc). Not all tubes are created equal and some are only intended to count cyclists – these may not contain vehicle speeds or classifications.