Ants Are Practically Immune to Traffic Jams
sciencealert.com
sciencealert.com
So an ant can go from full speed, to stopped, to full speed in a fraction of a second. A car on the highway will take several seconds to stop, and much longer to smoothly accelerate, leading to standing wave type effects on highways. This is much less likely with people walking, and even less likely with ants.
The dynamics of cars on the highway is governed by the difficulty of changing speed and direction. For ants, this constraint is negligible. So these things don't really compare.
I can "solve" a lot of traffic problems too, if nobody involved is worried about collisions.
Though based on my car's adaptive cruise control ability, we've got a long way to go before we can have cars that drive within a few feet of each other at highway speeds, and even longer before we could have intersections without signals (or stops).
All it takes is one rock dropping onto the road heavy enough to immediately stop a car in its tracks, and what would follow would be a series of collisions affecting a large number of cars.
Then you need to leave gaps for new arrivals from a different road, and in the end I don't think the efficiency would be that much higher.
I think the benefits are more that the car strictly obeys road rules, as opposed to humans being unaware, ignoring, or straight up willfully breaking (e.g. speeding) the rules.
<rant>
On my path to and from work there is a "trouble nexus" - you have a few main roads intersecting, a relatively short stretch of road with a couple of entrance/exits towards a public transit hub (trains, buses, and a large carpark converging - so there's a lot of road traffic), then a bridge, then another major intersection and exits onto a highway.
People are always slowing down to create a gap in the traffic flow and let vehicles from the transit hub onto the road leading up to the bridge, in an effort to be kind towards other drivers, but this has disastrous effects on the traffic behind it - interrupting the traffic flow of the major roads.
If people did not make space for vehicles from the side roads, the main flow of traffic would pass fairly quickly and then the sideroad traffic would be able to get on noramlly.
</rant>
The point I am trying to make is that autonamous cars would let traffic planners adjust e.g. road speeds, traffic light timings, etc. closer to a global optimum without having to account for human selfishness.
>"Traffic jams are ubiquitous in human society where individuals are pursuing their own personal objective," the authors explain. "In contrast, ants share a common goal: the survival of the colony, thus they are expected to act cooperatively to optimise food return."
If everyone drove 40mph during rush hour, we'd be well within capacity even with increased drivership. When everyone tries to go 65+mph, that's when things slow down to 5mph. Prisoner's dilemma here, not the limits of acceleration.
Just some bad highway design. Also places like the Embarcadero interchange at the 101 in Palo Alto has existing traffic fighting with entering traffic within 200 meters of space. HOV lanes make it even worse because you end up squeezing all the lanes and you create incentives for HOV drivers to merge all the way to the left as quickly as possible which further delays the main lanes since people are getting slowed down from the lane changes. Then, when HOV drivers have to exit, again they have to merge all the way right again. There is a bottleneck squeeze and the lateral squeeze happening as well. Houston traffic by comparison is “bad” but far better than the Silicon Valley version despite Silicon Valley having a smaller population and fewer cars.
Exit before/ merge after we much better than exit after/merge before. SV has many of these congestion building ramp strategies.
Momentum v strength doesn't scale linearly.
This sounds a lot like how traffic waves [1] occur. When there's a traffic jam ahead, you can often help clear it out just by slowing down to the average speed it's moving. Going a steady 10mph is much better than going 30mph for 1/3 of the time and then being stopped for 2/3 of the time. If everyone can start going smoothly at 10mph it will eventually speed up.
Traffic jams occur because cars are arriving at some point on the road faster than they can leave that point. If the cars coming towards it just slow down to allow the cars there time to leave, the jam will clear.
I saw one of these early one Saturday morning on I280 in San Jose. I presume it started with congestion during Friday night commute. It was still there at 7AM - cars adding to the back, slowing to a stop for an instant then starting up again and zooming away from the front. All for no apparent reason (no accident/no other congestion on the freeway anywhere).
That said, I try to clear those up when I see them.
Packs of 5 or more cars driving close to each other will try to merge in to the freeway with cars on the freeway, who also have little space between them. So eventually everyone needs to brake and it slows everyone else down.
And turn signals are seen as a sign of weakness -- cars will actually speed up to close a gap when you signal.
There is no way around stop and go traffic once the maximum capacity of flowing cars has been exceeded. After this, leaving extra space is just waste, which is why in more densely populated areas, people "cut" into the space in front, because the only optimization left is to use as much road as possible.
Whether or not the time saved is worth the wear and tear, environmental damage, increased risk of collision, I can't say. I'd say probably not, but it's going to happen anyway.
There is an efficiency gained through having space to change lanes as well, which is ine cause of the slowdown.
This is, in my utopian imagination, the best argument for automated cars. Which works great until a manufacturer, or enthusiast, decides to make an "aggro" AI which takes advantage of the selfless AI...
This is certainly true, people often falsely start the car instantly and continue to drive just to stop a few meters later. The safe distance not also is a safety measurement but also a good way to at least help to declutter the jam.
After a certain point, frequently exceeded in most cities, using more road capacity can't possibly declutter the jam. It will push the jam further back.
I'm not sure speeding up as fast as you can helps because usually there is another jam around the corner.
The barrier is the time it takes people to start to move, not how fast they do once they do move. Therefore start up immediately, but there is no point in zooming ahead. In fact it is counter-productive!
What really matters is reducing how many cars are stopped. Once that gets to zero, the jam can evaporate. Therefore when you see a jam ahead, slow down. Create space. And then try to just barely not have to stop. And when you come away, if there is any sign of a second jam create space and do the same.
The result is you save on brakes, create immediate frustration for any stupid drivers who happen to be behind you, and make life a lot better for cars 20+ behind you.
If just a few percent of drivers did as I suggest, stop and go disappears. In effect slowing in advance moves the congestion back earlier, reduces its size, and makes it easy to have it evaporate.
The reason that traffic jams happen is that freely moving traffic carries more cars per minute than stop and go. So there is a traffic volume where there are two states - everyone moving or traffic jam. But when everyone is moving, even minor slowdowns can cascade and switch states. And once switched, it is impossible to fix until traffic volume dies down and the hard stops are eliminated.
We can't easily fix traffic volume. But the strategy that I suggest eliminates hard stops without reducing cars per minute. And therefore causes the jams to go away faster.
Before folks complain: I only lane split up to 30mph and at speed differentials no more than 5. Those bikers you see zooming past and scaring the shit out of you are idiots.
The result is they tend to continue moving forward without the stop/start of normal cars. I just sit behind them in 1st gear or whatever and since no one wants to "get stuck behind a semi" people don't usually care if you leave the larger gap, so you don't have to deal with drivers sliding in front of you and eating up your cushion of space. My left leg isn't exactly going to atrophy from the lack of clutching, but it certainly does save it a fair bit of work.
Seems like good advice.
From what I can gather, I'd rather ride a motorcycle for my commute and lane split.
In Toronto I can ride for seven months of the year (Apr-Oct), and with the more moderate climate of the Pacific Ocean, it'd be possible to do it year-round. The occasional downpour during the wet season can easily be handled with Goretex(r). (I also pedal cycle some days of the week for commuting just to get some cardio.)
The problem is usually people merging in front, requiring that everyone else slow down. I don't see how steady speed is even really possible there, let alone how it helps.
Let's say everyone has a two-second following distance. Then each lane moves one car by every 2 seconds, and that's that.
I'm of a similar belief. However, I've run into self-proclaimed professional traffic engineers who insist the best thing is for you to tailgate the car in front of you as closely as possible. The provided justification was that the more tightly traffic is packed, the sooner people can reach their exit & free up space on the road. I still don't buy it.
Site was made in 1994, and looks like it. My friends and I spend hours on here in high school reading about all his interesting science experiments, and trying some out ourselves.
Yes, but, which problem are you trying to solve? The thing most drivers want to optimise is door-to-door time: slowing down as a solution is a tough sell!
People like to marvel at ants by taking everything they do and scaling it up. That’s not a valid thing to do, physically speaking. Kinetic energy is proportional to mass times velocity squared. Compared to humans, ants with negligible mass and very low velocity have minuscule kinetic energy when they collide.
;-) Sure, not as fast as humans, but seeing something small (and potentially with big poisonous pincers) move at that speed is a little freaky.
"To the mouse and any smaller animal [gravity] presents practically no dangers. You can drop a mouse down a thousand-yard mine shaft; and, on arriving at the bottom, it gets a slight shock and walks away. A rat is killed, a man is broken, a horse splashes. For the resistance presented to movement by the air is proportional to the surface of the moving object."
I see this happen almost daily, so I can only imagine how often it actually occurs when I'm not around to witness it. I wonder how much this slows the whole system down just so that a few folks can hopefully get where they're going one traffic light-cycle sooner. I'd be mortified to be sitting in one of these cars getting honked and glared at for my complete and utter lack of consideration towards others, but I guess selfishness is a powerful enough force to keep people driving like assholes regardless.
If you ever want to grab a coffee or something, let me know :) we’re also doing rust lunches every other week downtown.
Traffic cams could answer this question…
A corollary of the above fact is that autonomous cars won't save us. They might make traffic better by about 20%, but induced demand allows us to predict that speeds during rush hour won't actually get better. https://en.wikipedia.org/wiki/Induced_demand
EDIT: BuT WHaT abOuT DeLiVeRiEs?
Yes, I see a lot of abelism on NUMTOTs and the like. And I already get a ton of vitriol because my disability isn't very visible.
Yes, I do. I hope it is not shocking for you that people are treating you based on how you behave?
"We should make cities walkable and transport efficient and there are more efficient options than individual car travel" - probably someone smart and considerate.
"Cars were mistake from the beginning!!! Ban all death machines!!!!eleventy" - probably someone stupid and/or inconsiderate.
Not all of us are so enthralled with the rest of us. At some point in the last decade, I went from wanting to be constantly surrounded by others (youthful insecurity) to having my own life, doing my own thing, and not wanting to deal with other people’s bs.
The very wealthy can have a similar experience living in a city, but for everyone else, it means loss of independence and freedom. Plenty of people accept those tradeoffs, but please don’t shove it down the the rest of our throats.
Need something from the grocery store? 5 minute walk. Need something late at night? Store's still open, still a 5 minute walk. Need food late at night? I have the freedom of choice.
I feel no loss of independence by having city life all around me. If anything, living in a city has greatly improved my freedom. I don't need a car to get most places, I can do a variety of art and culture virtually every day of the week.
If I wanted to do large woodcrafts, access a tool library, access a laser cutter or a 3d printer, there's a maker's co-op about a 15 minute walk from my place with far more tools than I'd ever be able to amass even in a suburban house.
You may not prefer city life, but in no way does it represent a lack of independence or freedom.
Anyhow, I’m not saying there aren’t reasons to want to live in a city. I’m saying there are also good reasons not to want to, and I’m reacting to the suggestion that the means to do so be abolished.
That is a statement I do not understand at all.
(I've lived in suburbia, and rural America too, both in rich rural American and poor rural America. All of them are horrible for day-to-day living compared to anywhere I've ever lived in a city.)
My point is there is no solution fixing traffic jams in most cities or rush hours. If you've been to a poorer country with lax traffic law enforcement, you will see the extreme end of the situation play out where you can pretty much model all the vehicles as a fluid as they slowly ease by each other with whatever space they can find.
The amount of cortisol the human body releases in the average driving scenario is enough to make anybody far more irritable and prone to "selfishness" or anger on the road. Unlike on a sidewalk, one mistake on the road can and often does result in fatality and that tends to change one's attitude to something like potential collision.
Still, a lot of people don't do this, and it makes life harder for those who do. I'm amazed by how people will race to be the first one stopped at a red light.
Doing a greedy optimization for maximum instantaneous speed can reduce the overall traffic speed, and sometimes even the average speed of the driver in question, increasing their own trip time. But the greedy optimization is still common to see.
> When humans are walking or driving, the flow of traffic usually begins to slow when occupancy reaches 40 percent. Argentine ants, on the other hand, show no signs of slowing, even when the bridge occupancy reached 80 percent.
Your point (which is a good one) can be made even more strongly by saying
“From the article ...”
I can easily move double the speed on an empty sidewalk as I can the average mid-day mess. Humans absolutely have traffic jams on sidewalks.
>When it's moderately busy, for instance, the authors found the ants actually speed up, accelerating until a maximum flow or capacity is reached.
Then from the next paragraph:
>Plus, at high density times like this, the ants were found to change their behaviour and slow down to avoid more time-wasting collisions.
Did I miss something here or does this legitimately make no sense?
Then, on the next paragraph:
> And they do this through self-imposed speed regulation. When it's moderately busy, for instance, the authors found the ants actually speed up, accelerating until a maximum flow or capacity is reached.
Doesn't this mean that they do slow down?
Again, I'm speculating about the meaning but if I'm right then it's a poor choice of words from the author.
You know how in traffic jams everyone is breaking, then speeding up - just to slam their breaks again? Ants prevent the breaks part by moving slower in the first place, which improves the traffic flow.
Perhaps humans don't have the option of walking / driving through wherever they please, and instead they have to use fixed roads / sidewalk? I'm pretty sure if we had the option of driving on dirt we would easily avoid traffic jams, as we'd just drive wherever we want.
We'll be finally able to traffic jam free when flying cars become the norm.
From the article:
"they do this through self-imposed speed regulation. When it's moderately busy, for instance, the authors found the ants actually speed up, accelerating until a maximum flow or capacity is reached.
Whereas, when a trail is overcrowded, the ants restrained themselves and avoided joining until things thinned out. Plus, at high density times like this, the ants were found to change their behaviour and slow down to avoid more time-wasting collisions."
We'll be finally able to traffic jam free when autopilot will make us slow appropriately in high density conditions, avoiding accordion-like brake/accelerate/brake cycles
It looks wonderful! Just, please, add the option into your autopilot to let me pass before playing with the best jam-reabsorbing strategy!
I need to go places, not like the rest of you who hit the road just for fun!
No, because each vehicle has different acceleration and deceleration rates. Watch any road with an incline and you will see congestion develop relatively quickly before the incline.
And a traffic jam is inevitable when the bandwidth of a road has been exceeded. Each vehicle needs a certain amount of space in front of it, and behind it. The faster it goes, the more space it is, as well as if it’s heavy. This means for a given number of lanes, at a given speed, there exists a max number of vehicles. Once this maximum is exceeded, speed must drop as it is no longer safe to travel so close to vehicles in front and behind, and so bandwidth also drops. Hence, traffic jam. The different accel/decel rates contribute to the congestion also, as vehicles need varying amounts of time to fill the space in front of them.
Bottom line, there is no solution to traffic jams other than reducing space needed to travel Per person (trains instead of cars), or increasing speeds (not possible in cars on current roads without exceeding acceptable safety risks), increasing the number of lanes (space is usually not available), and the easiest option, reduce the number of vehicles traveling the road via variable tolling based on congestion (currently the best option in my opinion).
Also, I would assume any congestion alleviated would be offset by induced demand by the people who now see less congestion and decide its worth it to jump on the road.
Proportional to the number of people forgoing trips because the congestion sucks. You'll never eliminate all congestion at peak hours but you can make "peak hours" into "peak hour" if you make things more efficient. A more efficient system can also withstand more traffic before things start backing up into each other and it all goes to hell with feedback loops.
Scenarios where individuals are planning their own movement (road traffic, foot traffic in a stadium, etc) can generally be modeled like a plumbing system carrying a highly viscous and compressible material. If you throw every trick in the book at it to make all the "features" (intersections, doorways) efficient you can reap a lot of benefits without actually widening bottlenecks.
Attacking the other parameters of the problem is nice, but not the best use of resources. But perhaps that’s all we can wish for at this point.
Everyone in the USA is required to drive a 6 sqm hybrid Fiat, effective immediately.
In particular, they are working as a team. No single ant has any incentive to move faster than their teammates: the nest will be filled at the same speed, whether she gets there first or others do.
"A microwave-powered aircraft has lifting surfaces for exerting lifting forces on the aircraft in response to the propulsion of the aircraft and a rectenna array for receiving and rectifying microwave energy transmitted to the aircraft from a location remote from the aircraft. An electric motor for driving a propeller is energized by microwave energy received by the rectenna array, which is provided in a body at the underside of the aircraft. The body has its major dimensions extending horizontally and is relatively shallow with a periphery which is vertically curved so as to reduce turbulence in the airstream over the body during flight. The body is separate from the lifting surfaces and shaped to at least substantially avoid the generation of lifting forces by the body."
https://patents.google.com/patent/US4955562A/en
How much energy can a microwave emitter send across how far? If we're talking tens of kilowatts at a distance of 5-10 miles - emitter "turrets" would be situated on towers along a path between cities. Depending on the energy storage method aboard the passenger-ferrying aircraft - the tower would be sending a charge for the duration of a straight flight path travel time of several miles. If the craft has the energy storage for an average 50 miles of travel (70 miles after adding a safety buffer), then every 30 miles the craft would receive a charge behind a shield to protect passengers from intense microwave radiation focused on its rectenna.
If the towers have a range of 5 miles, then that is 10 miles of charging since the craft flies towards, over, and away from the tower. Duration of a charge could increase if the craft has the altitude to glide and thus slow and stop running engines. Microwave induced amperage can increase as the craft gets closer to the source. Since this is for inter-city travel, the towers would be located on empty land where dozens of hectacres of solar panels could provide a local dedicated grid. Night flight may not be feasible unless there is a local dense energy source. We have to consider passenger air travel (likely automated) as traditional traffic, along a straight line, like Coruscant. Multiple towers and emitters at these charging points for high density intersections or for two way "highways".
This could only work if these microwave emitters can send out high energy in a very narrow beam with the turret focusing precisely on the craft. It will kill any living thing in that path. Bird populations. Insect migrations. Unshielded passengers.
Also see:
https://en.wikipedia.org/wiki/Electrolaser
This type of "fueling station" means less weight required for the flying car's energy storage method. Traffic path charging happens intermittently at flight speeds instead of idled.
... probably just best to use a dense energy source and "fill up while parked" the traditional way before each trip?
> Monderman's work demonstrated that city and village streets become safer when they are stripped of traffic controls so that drivers must take cues from observing people rather than signs. Though it sounds chaotic, the results of Shared Space have shown to be just the opposite: traffic moves slower and the rate of major accidents declines drastically.
> His design approach is the concept of "shared space", an urban design approach that seeks to minimise demarcations between vehicle traffic and pedestrians, often by removing features such as kerbs, road surface markings, traffic signs, and regulations. Monderman found that the traffic efficiency and safety improved when the street and surrounding public space was redesigned to encourage each person to negotiate their movement directly with others.
https://www.pps.org/article/hans-monderman
https://www.pps.org/article/shared-space
https://www.maharam.com/stories/rawsthorn_hans-mondermans-na...
For the record:
> First implemented in his native Netherlands, Monderman’s designs have since spread throughout Europe, South Africa, Australia, Japan, and Brazil, and Canada. They are also making an appearance in often car-dominated U.S. cities such as Pittsburgh, Seattle, Portland, San Francisco, and Chicago.
> "It's a moving away from regulated, legislated traffic toward space which, by the way it's designed and configured, makes it clear what sort of behavior is anticipated," said Ben Hamilton-Baillie, an English urban designer who coined the phrase Shared Space after trying out Monderman's controversial ideas in his hometown of Bristol. Hamilton-Baillie now promotes Shared Space projects in Germany, Belgium, and Denmark as part of an ongoing project of the European Union.
- in Vienna, they give priority to pedestrians in such shared zones, cars have to go very slowly and often struggle with large numbers of people in areas frequented by tourists. There is also a lot of confusion around the question where cars are actually allowed to go and when
- in some tourist areas in Italy, where lower traffic roads have no sidewalks and cars go 30 Km/h, pedestrians walk on the edge of the street. This seems just as safe and less frustrating for drivers.
If I want to get home I don't have much to gain from 10 other people coming home first.
Of course, in a fully autonomous road network this is both possible, and mostly unnecessary, as nobody has to stop at traffic lights any more. Apart from pedestrian crossings of course.
In army you trust others to move with you.
In car, you know that others won't move anyway so you wait and react to their behaviour.
Army also moves in cohesive manner - unit is going towards known place.
Car drivers do not know where others want to drive.
Even the purpose of turn signals evade most drivers - they exist so you can signal your intention BEFORE manoeuvrer - most drivers turn them just before they need to, or even during the manoeuvrer.
In the army some chief gives the instructions. Everyone obeys the instructions (regardless of whether you trust or don't trust your adjacent soldiers to move as well).
Seems the problem really is just the lack of co-operation and individualism that produces a negative externality for the society as a whole.
This type of behavior often causes the 'out of nowhere' traffic jams. Someone brakes excessively because of one of the reasons above and people behind them brake even harder. Eventually some people will come to a stop and this will accordion for a while.
You can play with this here: https://traffic-simulation.de/
Especially try just disturbing an otherwise nice traffic flow.
This second point is basically saying that if there's a pileup, yes the whole roadway will stop while it's cleared, but the moment a lane opens up, autonomous cars will be able to more efficiently and immediately use it to get the whole jam moving forward.
There is also traffic-jam in this species if we narrow the path. Here, also there is no change in dynamics in the way these ants relocate even when there is traffic jam (to be published). Interesting to see similar methods adopted by ants even though the transport method is different.
Humans need externally imposed incentives to act cooperatively, which is where government and private property comes in.