In the United States, you can sometimes find rubber hoses stretched across the carriageway. Why do you think this is done?
And this is done in order to carry out various measurements. Passing through the hose, which is called the “road pneumotube” in the US Department of Transportation, the machines are driving air out of it, which allows such measurements. One end of the hose is sealed, and the other end is fitted with a valve. The receiving device reads the signal from the valve. Towards the carriageway hoses are fixed with screws or studs.
So you can count the number of passing cars, getting information about the distribution of transport load by the hour or days of the week. Adding a second hose allows you to measure the speed of passing cars.