That Purple Line On The Edge Of The Motorway

What is up with that Purple tube that runs alongside the motorway ? Who put it there? Why is is there? And where on earth does it lead? What is up with that Purple tube that runs alongside the motorway ? Who put it there? Why is is there? And where on earth does it lead? What is up with that Purple tube that runs alongside the motorway ? Who put it there? Why is is there? And where on earth does it lead? What is up with that Purple tube that runs alongside the motorway ? Who put it there? Why is is there? And where on earth does it lead?