means a set of colored lights installed at intersections to take turns telling different streams of traffic to stop or go, replacing chaos with a shared fiction of order.

from the first one appeared outside the british parliament in 1868, gas-lit and manually operated, and exploded weeks later, injuring the police officer running it; the modern electric version was patented in the united states in the 1910s as cities drowned in horses, streetcars, and the new menace of automobiles.