I beg to differ, and that's a criticism I also have for the OP:
From my humble observations, traffic jams are caused because too much traffic (x cars/sec) flows into a bottleneck, i.e. something that can't allow x cars/sec to pass through. Whenever I get into a traffic jam, I play "spot the bottleneck" to ease my boredom, and so far I haven't found a case where there was none.
Transient traffic jams like the OP described seem to get solved by people accelerating as much as they can once they're past the jam. If there's no bottleneck ahead, they're indeed transient.
Of course there's a reason for the traffic jam, but people make it far far worse by tailgating.
I saw some fantastic traffic jams in China. There'd be some incident on a highway (not the toll highways, but the badly supervised free ones between nearby cities). People would drive on the wrong side of the road to get around it; on both sides. Eventually, there'd be thousands of cars backed up, on both sides of the road, unable to move more than a few feet. It was good news for the nearby shopkeepers, who'd have people leaving their cars to get something for dinner (since they couldn't move anywhere) - this did cause some issues when the traffic started moving again though.
But yes, originally a truck had broken down under an overpass or something, so arguably that was why it all started.
I agree with this observation. I cringe when I hear other comments talking about people driving through traffic trying to smooth out traffic waves. I am very suspicious about the claim that this speeds things up for anyone.
People accelerating hard and braking hard is not good for traffic, but if there is some guy moving slower than possible on a highway with a lot of commuters, many people will need to change lanes to avoid that obstacle. That is not good for traffic either.
Bottlenecks caused by an accident or merging lanes on a motorway are one thing, but I've seen traffic jams where the bottleneck was a disabled car that was well clear of the road, or the police have pulled someone over. In those instances there's no good reason to have a jam.
Well, there's a reason, it doesn't matter if it isn't good: other curious drivers. Here in Israel, traffic reporters on the radio routinely implore the listeners not to slow down and take a look, since it causes jams.
My point is, whatever causes a segment of the road to only allow x cars/sec will cause a bottleneck if there are more than x cars/sec incoming flow, regardless of whether it is inherent or not.
From my humble observations, traffic jams are caused because too much traffic (x cars/sec) flows into a bottleneck, i.e. something that can't allow x cars/sec to pass through. Whenever I get into a traffic jam, I play "spot the bottleneck" to ease my boredom, and so far I haven't found a case where there was none.
Transient traffic jams like the OP described seem to get solved by people accelerating as much as they can once they're past the jam. If there's no bottleneck ahead, they're indeed transient.