Two or more snowplows
plowing a multi-lane highway in a specific fashion where the one in the innermost lane is just a few metres ahead of the next one, and so on, ensuring snow is
bumped from the inside lane right on out to the outside shoulder.
Also known as "
echelon plowing."
"It took me hours to get home. I
got stuck behind a
congo line."
"We've had 6
cm of snow within an hour and the congo lines are already out."
