This afternoon I blundered downtown into a pretty busy 6 or 8 lane by 6 or 8 lane 4 way intersection with non working traffic signals. Nightmare is an understatement.
The rule is simple enough, of course. No signals equals a four way stop. What happened was that cars from most every direction ended up in the center of the intersection effective blocking traffic in every direction. Helpful drivers continued to pull into the intersection blocking those already in the intersection from forward or backwards progress.
It was. awful.