Anyone commuting to work by car regularly encounters closed lanes that lead to congestion and delays. Maybe it’s a three-lane expressway that suddenly loses one lane, one-third of its normal capacity. Squeezing an urban highway’s capacity is expensive business. Delay costs for a few thousand commuters add-up quickly.

There are usually good reasons for lane-closing. Maybe it is an accident that has to be cleared away or a needed highway repair to be completed. The capacity lost is temporary. But always, there are artificial yellow and black barrels, or maybe rubber pylons, put in place to close off capacity.