Original film · Traffic waves
How Phantom Traffic Jams Move Backward
Give one car a brief brake pulse and see how a slowdown can travel backward even while every car keeps moving forward.
Transcript
Can one brief brake tap create a traffic jam? Give the same car the same pulse in this model. With fewer cars, larger gaps give the following drivers room to recover. Now add more cars and repeat the pulse. Each driver responds to the gap ahead, and the slowdown can pass from car to car. Watch the road beside its time plot. Cars move forwards while a queue can travel backwards. The result depends on the settings; this is a simplified road, not a traffic forecast. Compare the two runs at Explainer Tools dot com.