build down(redirected from built down)
To decrease or lessen. That group encourages the government to build down on wasteful spending. Give the traffic some time to build down before you leave the office—otherwise, you'll just sit on the highway for an hour.
[for traffic] to reduce in volume or diminish. At about six, the going-home traffic begins to build down. When traffic builds down, I leave for home.
Reduce, diminish, as in Owing to increased vigilance, traffic in narcotics is finally building down. This term, the antonym of build up, came into use about 1980 with regard to reducing the stockpile of nuclear weapons and soon was applied more widely.