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A Single Autonomous Car Has a Huge Impact on Alleviating Traffic

7 points by sprucely 9y ago

eridius 9y ago
Watching the video, it looks to me like the key result here is "leaving a big gap in front of you helps smooth out phantom traffic jams", because that's basically all the autonomous car did when the traffic jams appeared. It's also not clear from this video if this actually helps with "real" traffic jams. The simulated jam here has a very important difference from real ones, which is everybody's going in a circle, so once a car hits a phantom jam, they'll keep hitting the same jam repeatedly as it goes around the circle until the jam is cleared up. But in real traffic, once you hit a phantom jam, you'll never hit the same jam because it proceeds behind you and doesn't wrap around. Which is to say, an autonomous car might be able to smooth out future phantom jams once it hits the first one, if there are a sequence of jam "waves" instead of just one big one, but in that first one it doesn't have the buffer in front of it yet. It might still be able to help a little by building a buffer as it proceeds through the jam in order to reduce the need for cars behind to keep accelerating and braking, but it won't be able to kill the jam. And actually, come to think of it, there's another key difference here with a real traffic jam, which is traffic jams generally occur on high-occupancy roads, which generally means multi-lane roads. So if an autonomous car builds a big buffer in the middle of a jam, cars from other lands are just going to merge in front of it, eliminating the buffer and preventing the autonomous car from actually doing anything useful.
- TFortunato 9y ago
  Yeah, not sure what the big news is here... "traffic waves" actually have been talked about for a long time... I remember reading "the science hobbyist" pages almost 20 years ago (!), about this. I think besides the fact that the car is autonomous, and maybe more consistent than a human driver would be in this situation, there is nothing really new here. http://trafficwaves.org/ http://trafficwaves.org/
- vannevar 9y ago
  I think the implication of the simulation is not that a single car alleviates jams, but as few as 5% autonomous vehicles could have a significant impact. The title of the article is a bit misleading.

7 points by sprucely 9y ago

Watching the video, it looks to me like the key result here is "leaving a big gap in front of you helps smooth out phantom traffic jams", because that's basically all the autonomous car did when the traffic jams appeared. It's also not clear from this video if this actually helps with "real" traffic jams. The simulated jam here has a very important difference from real ones, which is everybody's going in a circle, so once a car hits a phantom jam, they'll keep hitting the same jam repeatedly as it goes around the circle until the jam is cleared up. But in real traffic, once you hit a phantom jam, you'll never hit the same jam because it proceeds behind you and doesn't wrap around. Which is to say, an autonomous car might be able to smooth out future phantom jams once it hits the first one, if there are a sequence of jam "waves" instead of just one big one, but in that first one it doesn't have the buffer in front of it yet. It might still be able to help a little by building a buffer as it proceeds through the jam in order to reduce the need for cars behind to keep accelerating and braking, but it won't be able to kill the jam. And actually, come to think of it, there's another key difference here with a real traffic jam, which is traffic jams generally occur on high-occupancy roads, which generally means multi-lane roads. So if an autonomous car builds a big buffer in the middle of a jam, cars from other lands are just going to merge in front of it, eliminating the buffer and preventing the autonomous car from actually doing anything useful.

TFortunato 9y ago
Yeah, not sure what the big news is here... "traffic waves" actually have been talked about for a long time... I remember reading "the science hobbyist" pages almost 20 years ago (!), about this. I think besides the fact that the car is autonomous, and maybe more consistent than a human driver would be in this situation, there is nothing really new here. http://trafficwaves.org/ http://trafficwaves.org/
vannevar 9y ago
I think the implication of the simulation is not that a single car alleviates jams, but as few as 5% autonomous vehicles could have a significant impact. The title of the article is a bit misleading.