Congestion Lock

In any practical sense it is impossible for motorways (or most roads) to become gridlocked as is so often described in news reports.

Gridlock is a feature of roads laid out in grids (the clue is in the word) and is made more likely by roads having alternate one-way systems - as in Manhattan. Cars line up around the block and cannot move forward or turn due to the car(s) in front - as illustrated below courtesy of Wikipedia.

In the right circumstances it can be achieved with only four cars in a square (or grid). Generally speaking gridlock would be of minimal interest in news terms.

News is interested in congestion as more people are involved and the pictures are better, but news prefers the word gridlock.

Stupid!