I witnessed this as a pedestrian many years ago...
The scene: a "T" intersection in a small New England town where the streets
are not overly wide. There's a small concrete island a few feet long and a
couple feet wide dividing the one (vertical) street where it joined the cross
street of the T. Two cars are waiting to enter the cross street; the one at the
head of the line wants to turn left.
A car travelling from right to left on the cross street apparently wanted to
turn around, so they turned left down the T and canted their car to make a
U-turn around the bottom of the island, which they couldn't complete because of
the two cars already waiting there. But another car had followed the first down
the T, and a third car behind them also started to turn left, but couldn't
complete its turn because the first car had stopped, and thus it was stuck
diagonally across the intersection, blocking both lanes of the cross street.
Now five cars are stuck in a small circle and no one is going anywhere.
When I saw this situation develop, I stopped in my tracks to watch it play out.
I waited for the driver of the first car to follow the chain of causality and
figure out that what was ultimately preventing them from making their (illegal)
U-turn was... themselves! And that the only way out was to abandon the U-turn
and continue straight down the T. It took the better part of a minute...
"The ultimate result of shielding men from the effects of folly is to fill the
world with fools." -- Herbert Spencer