The reel - bigger than most cars and nearly as tall as a lorry - was filmed as it veered across a five-lane highway on Vienna's A23 motorway.
As cars, vans and trucks tried to steer clear, the empty reel kept up a steady speed as it rolled diagonally over the carriageway.
Accident investigators believe the reel - once used to carry copper or electrical cable - fell off the back of a flatbed truck and its momentum from the fall kept it moving across the A23.
The video - shot by a lorry driver - went viral across Austria with more than 100,000 views in a few hours.
As he complains about the slow-moving traffic, the trucker can be heard bursting out laughing after he sees the cause of the jam.
In Vienna, the A23 is viewed with as much dread and suspicion as the M25 ring road in London and the south east.
One Austrian driver who saw the reel said: "I spotted it yesterday evening. Everything is possible on the A23!"
Story courtesy of Central European News.