A major oversight here is rate of acceleration. Every organism and vehicle on earth has the same gravity and similar coefficients of friction to work with, so rates of acceleration have roughly the same cap, but the speeds change by orders of magnitude.
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 think that's part of the promise of self-driving cars -- they'll ostensibly be safer, so can drive closer together, and can cooperate at intersections to increase throughput, no one needs to stop, just adjust speed to allow a gap.
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).
I don't know if this promise will ever be real in that extent. Even if you assume perfect drivers(automatic or not) with instant reaction speed there can be situations where a road can become impassable quickly due to external influences, and this alone makes short distances between cars unsafe.
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.
Presumably autonamous cars would maintain proper separation - I try to maintain a three to five second gap between myself and the next card, but drivers in my area tend to be quite aggresive and will force their way into the gap - I have nearly been hit or run off the road multiple times.
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.
Eh, I feel like that's a rather small factor compared to the main reason we experience traffic jams (tragedy of the commons) and ants do not:
>"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.
I've wondered the same thing about the effect of slow-accelerating trucks on stop-and-go bay area freeway traffic during rush hours. I feel that the effects are fairly non-linear as more of these vehicles are introduced. Some cities in India don't allow heavy vehicle traffic on congested roads during peak commute hours, though I'm not sure if there's been a study of traffic patterns that validates/simulates these scenarios.
Pretty sure Bay Area Traffic is only negligibly affected by big trucks. It’s, in my experience because they have these ridiculous bottleneck merges (a two lane merge, plus that ridiculous diamond lane, merging into a single lane on the destination highway. It’s like a Venturi. Then there are “exit only” signs designating a lane that isn’t exit only. The 101 south just before the 85 has this problem: you think it’s exit only but it isn’t.
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.
I used to wonder about this often, and many years ago wrote simulations to model traffic. The introduction of connected on/off ramps were the main cause of congestion due to acceleration, merging, etc.
Exit before/ merge after we much better than exit after/merge before. SV has many of these congestion building ramp strategies.
> Whereas, when a trail is overcrowded, the ants restrained themselves and avoided joining until things thinned out.
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'm no traffic jam expert, but driving manuals in west coast traffic (Highway/Interstate) has taught me its best to find a large semi-truck, ideally with an empty flatbed trailer, and just follow it. The semi driver doesn't want to ever completely stop (if they can avoid it), they have a much better view since they're somewhat higher up, and they accelerate/decelerate much slower, so its easier to predict their movements.
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.
> I'm no traffic jam expert, but driving manuals in west coast traffic ...
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.)
Took me a minute to realize by "driving manuals" you meant driving a manual transmission car. At first I thought you meant the behavior you described was recommended by the drivers manual that the licensing test is based off of. :)
I use this method to an extent, but the unfortunate result often becomes people zipping in in front of you when you inevitably have a bit of extra space compared to those around you. This seems to leave you with two problems which are hard to solve simultaneously. The first is the one you mention where you want to keep a mostly constant speed compared to the whole group. The second is the effective need to locally keep up with the cars around you. Solving both problems simultaneously seems essentially impossible. I guess removing self-interest is the only real way (which appears to be what the ants do).
The slow-n-steady method really only works with a critical mass of participation. Unfortunately most people either don't know that it helps or don't care and are happy to just keep stomping the gas and breaks repeatedly.
Slow and steady only works up to a certain vehicle density. Once that has been exceeded, slow and steady simply serves to cause congestion further back in the road than necessary.
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.
If everyone did it, it would be material. But everywhere I've seen, other people usually slip into whatever space there is. Which technically does maximize the rate of vehicles passing through a point in the road, as you can take advantage of the various rates of acceleration.
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.
Not really, as mentioned in a sibling thread. If you’re in a big hurry, simply leave two minutes earlier you’ll be ahead of all the folks you’re worried about.
There is an efficiency gained through having space to change lanes as well, which is ine cause of the slowdown.
Someone always responds with this, but the reality is that it doesn’t matter. Will you arrive later if one car jumps ahead, or ten? Might delay you an extra minute. If that is a problem simply leave one minute earlier, haha.
It's not that. It just makes the thing harder to do. If someone cuts in front of you, they frequently will brake too, and your previous speed will bring you up to them.
> I guess removing self-interest is the only real way (which appears to be what the ants do).
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...
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).
The other problem in the Bay Area is that cars don't know how to merge and no one wants to let another driver in front of 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.
you can often help clear it out just by slowing down to the average speed it's moving
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.
Does the steady-speed method work, even with cooperation?
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.
As a motorcyclist I help by zipping around, lane splitting at safe speeds, and generally getting the hell outta there. It’s hard job, but someone’s gotta be the free radical.
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.
I checking out recommend http://amasci.com/ by the same author: Bill Beaty.
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.
> Traffic Jams occur because cause are arriving [...] faster than they can leave
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.
>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 often think that when exiting a jam (the point where cars begin to speed up) that the best thing one can do for everyone behind you is speed up as fast as you can. I've never modeled it or anything, but does this seem true to the folks here commenting on HN?
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.
It's impossible to do this as each and every car has different acceleration and deceleration. The stop and go flow is inevitable. Trying to keep your car rolling is good, especially for wear and tear, but leaving excess space in front is also bad due to increasing the length of the congestion behind. The only solution is for cars to enter the congestion at a lower rate than they exit the congestion.
We rarely accelerate/decelerate to the limit of the car, and therefore should choose.
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.
If I can see the next section of stopped cars, I will slowly accelerate and time it so that by the time I reach them, I don't have to stop and can continue driving at a somewhat constant rate.
I'm not sure speeding up as fast as you can helps because usually there is another jam around the corner.
Don't speed up faster than the person in front of you, or you might end up having to touch the brakes and create a new traffic wave that propagates backward again.
> If the cars coming towards it just slow down to allow the cars there time to leave, the jam will clear.
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!
Looking at that video, a lot of the ants were walking into each other. Maybe their advantage is just that collisions have low cost so they can afford to use strategies that even among humans on foot would lead to a painful crash.
Yeah exactly. Ants also move far slower than humans do. Even the world’s fastest ant only moves about 1 m/s, considerably slower than the average human walking speed of 1.4 m/s.
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.
Because ants are small... And lightweight, I can’t remember right now the term for volume vs mass when compared, but you can throw an ant from the Empire State Building, and it will land like dropped from 2 inch height.
Taken from the Wikipedia page on terminal velocity, and quoted from the biologist J. B. S. Haldane:
"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 imagine an ant's drag coefficient is fairly high... and combined with the relative strength of the exoskeleton, they may as well be a powered armor trooper equivalent.
There is just no need to walk in to someone else since you can see far ahead and can plan a course around anyone else. I have watched ants and they always stop for a period of time after bumping which seems very inefficient when there is plenty of room to not bump
I live and work in downtown Austin. I frequently walk (about a mile each way) to/from my office, so I spend a lot of time interacting with and observing traffic patterns in a very automobile-congested area. One of the biggest issues I've witnessed is how frequently drivers will proceed into an intersection even though there isn't enough space ahead of them to clear the intersection. Then, the signal changes, and they are left blocking one or more travel lanes perpendicular to their vehicle, thereby spoiling the precious open road for the unfortunate motorists who are left to deal with their selfishness or inattentiveness.
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.
I also live and work in downtown Austin, and see this all the time too. It's... less than ideal, for sure. At least when people block the pedestrian crossing, (which is also something I encounter daily) it just makes it awkward, rather than gumming up traffic too.
The hilarious thing is that the two intersections I see this happen the most at...are two of the intersections that have this sign. Maybe if the City actually enforced the $500 fine, people would think twice. One operator with a few cameras could handle most of the downtown area, but, alas...
Because they're not ant roads, they're ant sidewalks? How can someone have such a blind spot of basic facts. Check out any street fair or large public outdoor event. People are going everywhere, despite a high density of people. It works because people are not driving.
> 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.
I don't know where you walk, but where I walk the sidewalks are jammed full of people legitimately moving slow due to injury or disability and people rudely just standing still and leaving it hard to imagine they could block more space if they tried.
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.
I have not read the studies but do they say anything about ants that are just standing still (if they would even do that in this situation) or injured? Is it taken into consideration?
It's kind of amazing how selfish people become once they are driving a car. If people drove in a way that focused on keeping traffic flowing it would work, but cars are just big ego bubbles.
This is commonly believed but untrue. A certain volume of vehicles will drastically slow a road, regardless of how well people drive. Unless by "drove in a way that focused on keeping traffic flowing" you mean "wait in the on-ramp merge lane until rush hour ends".
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
Cars are truly one of the mistakes the human civilization latched on to. With fossil fuels going out of fashion, cars need to go too. We do not need car not even battery powered car. Maybe one car per 100 people is what should be okay for emergency purposes.
That kind of extremist minorities are far too often found working in journalism, so-called science (rather academic activism), politics etc. ... So I'm not too optimistic about these trends.
Why? So that people can be forced to live in cramped cities, constantly share their space with rude, smelly, or violent strangers, and suffer the loss of freedom that necessarily entails?
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.
I can walk 10 minutes to get on a train that gets me many places in the city, 5 minutes in a different direction to get on multiple buses to go places the trains don't. No need to worry about parking.
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.
I live in a city right now, and sure, the grocery store is right there, but it’s also very expensive and has a tiny selection. I can get all of the same foods for much less in the suburbs and much more conveniently than carrying several heavy bags for multiple blocks.
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.
Getting in a car and driving a couple of miles through stop signs, traffic lights, winding suburban boulevards, and cul-de-sacs is more convenient than a five minute walk to the store? Or, if you're really in a rural area, getting in the car and driving for 30 minutes to get to the nearest small grocery store, as opposed to a five minute walk?
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.)
This argument keeps popping up, and it's a waste of thought. We'd OBVIOUSLY have cars or other kinds of provisions for disabled people! Do you actually think anti-car people are actually that stupid or inconsiderate?
> Do you actually think anti-car people are actually that stupid or inconsiderate?
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.
Maybe it's not your objective, but comments like this would be a lot more convincing if they were accompanied by a proposal for replacing cars and especially a steel man of the pro-car position.
Is it untrue? For example, traffic waves cause traffic jams. Traffic waves could be avoided, or significantly lessened, if people left more room while driving.
That only applies up to a certain density of vehicles. Due to differences in acceleration and deceleration of cars, trucks, other types of vehicles, and inclines and declines, after the number of vehicles surpasses the maximum capacity at a certain speed, the will have to slow down and speed up and slow down and speed, and there is no choice but to sit through until you get to a piece of the road that isn't congested.
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.
This has nothing to do with cars, pedestrians are just as selfish, if not worse (at least in cars they mostly follow basic rules/laws). I'm a fast walker and get annoyed every day with people who are ignorant of their surroundings, don't care about blocking all traffic (e.g. 2 slow fat people walking next to each other and taking up the whole width of the sidewalk), rudely bumping into other people or standing right in the middle of an obvious chokepoint (bloody tourists usually).
Traffic doesn't exist because drivers are selfish. Congestion is a fundamental property of the dynamics of the system. As the number of cars per unit area goes up, the speed of those cars goes down, The road's capacity is a product of these two numbers and there is an inflection point at (iirc) 40% car density. If the road's capacity drops, then the traffic that feeds into it will be greater than the traffic that flows out of it, further increasing the density, and dropping the capacity.
The maximum (practical) speed depends on the cars per unit area, but drivers can voluntarily drive slower than this. By looking ahead at the conditions down the road, such as traffic jams and red lights, you will often notice situations where there are big benefits from slowing down more than you are forced to.
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.
I think it's less about people being selfish (though some certainly are) and more about the metal bubbles that weigh about the same as an adult elephant and move at ridiculous velocities, all at the behest of strangers who should (but may not for various reasons) know what they're doing.
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.
My toughts exactly. People seam pretty efficient kind of flowing like water, creating line that advance towards some direction, adapting to moving obstacles almost never slowing down.
https://youtu.be/Od6EeCWytZo?t=51
Even cars in traffic without rules seem pretty efficient if you take into account how limited is the range of motions a car has and how human driver only has a limited perception of the area the vehicule is taking. https://www.youtube.com/watch?v=mrjqS5zd268
Basis of the article is questionable. Humans slow down on traffic to avoid accidents. Ants don’t have that constraint. Neither will ants cause a stampede and can suffocate to death.
At low density, ants move at a speed that maximizes efficiency. At medium density, they move a bit more briskly, sacrificing some energy to keep from blocking traffic. At high density, they move more deliberately, avoiding situations like we see on highways where a single vehicle advances rapidly but slows down many others as they brake to avoid it and cause a traffic wave.
They were probably "found" by another "foraging party" of their own colony. Even if one of them regains active pheromone trail, all of them can safely return.
> In fact, compared to humans, these ants could load up the bridge with twice the capacity without slowing down.
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.
I'm speculating that "slow down" in your first quote means "the flow doesn't plummet towards zero when it's busy" and in the second quote it means "reduce their average velocity". So in that sense they don't slow down (i.e. the colony doesn't grind to a halt) because they slow down (i.e. literally slowing down)
Again, I'm speculating about the meaning but if I'm right then it's a poor choice of words from the author.
Yes individuals slow down, but it prevents the "traffic jam waves" you see with humans. Essentially each individual ant is going slightly slower so that the average throughput stays the same.
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.
"Traffic jams are ubiquitous in human society where individuals are pursuing their own personal objective,"
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.
Ants can create new paths on demand. Ants on a trail typically have the same destination. Ants aren't going to park on the already tiny trail unlike humans. Bumps, potholes slow down cars and limit ability to increase speed unlike ants.
We'll be finally able to traffic jam free when flying cars become the norm.
That's not what the article is saying. They have tested ant flow on narrow bridges where additional lanes aren't possible.
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
> 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
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).
Humans don’t closely approach the theoretical limits of highway capacity. They encounter a much lower limit and get stuck in a range of suboptimal choices.
I can see it helping a little in cases where congestion is caused by some less than ideal braking, but in urban areas where the congestion is frequently due to merges or in a hilly area where trucks are going slower in one or two lanes, I don’t see it helping much. In rush hour, the cars are bumper to bumper, it’s because of all the cars entering the same roadway needing to merge in.
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.
>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.
The principle is sound, but the ants actually obey the rules whereas (in the UK at least) a small contingent of human drivers will ignore the limits, speeding up and slowing down between enforcement cameras. This concertina effect from just a small number of drivers is enough to slow the entire flow of traffic.
It would have happened anyway after a certain density of vehicles is exceeded, since each car and truck had different accel/decel rates. Especially if there is an incline anywhere.
yes, speed reduction on the Paris belt was also done in order to reduce traffic jams. The argument was "peak speed is slower, but apart from night/holidays situation with empty road, you'll actually get faster to where you're going because of less jams"
> Ants on a trail typically have the same destination.
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.
Flying cars will never become the norm unless we work out how to produce infinite clean energy or how to turn off gravity. Traffic jams will be gone when city planners work out cars were not a good idea for transporting mass amounts of people.
As far as flying car charging stations go - we could use large microwave emitters (narrow beam):
"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."
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.
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.
> 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.
This line of thought has become very popular among city planners here in Austria, but I've seen it implemented in 2 different ways:
- 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.
I think this article implies we operate like an ant colony with a single goal. I may be mistaken but we humans dont't have a single goal so our priorities are different.
What has always puzzled me is that how is it possible that for example in the army a unit of thousand men can move as a single unit. Yet 5 cars stopped at the traffic lights can't do this but exhibit a latency accumulating between every single vehicle. If everyone just started moving when the light turns everyone could take off at the same time!
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.
Yes it was a rethoric question but anyway you said it and there's basically the answer to the question posed by the scientist. Trust and communication.
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.
Except, if that were the case, all of the cars would then be travelling in very close proximity to each other. This would only work if we all stopped at the lights with the same space between stopped cars as moving cars.
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.
CGP Grey did a really nice, concise video on the topic of traffic and he addresses your point in the first 30 seconds.
Coordination, not cars, is the problem.
Watching someone improve traffic of game cities on Youtube I realized that traffic jams have more to do with how streets are laid out than with the behavior of drivers. If a city or more broadly speaking the street network was properly designed traffic jams would only happen in case of accidents or other unforeseeable traffic loads.
You're working on the assumption that game traffic is a perfect representation of actual traffic. In reality, that's not the case though. In games, traffic on a straight road behaves perfectly. In real life, people cut others off, forget to check their blind spots, play on their phones, etc.
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.
No, not in that game. People would cut into each others line all the time and generally behave stupidly. Also, if you have a traffic line where the behavior of the car in the front affects the cars behind it you already have bad traffic, which wouldn't happen with properly designed roads.
Actually really interesting to think about how self driving cars would be impacted. In a world where 100% of cars are self-driving, but algorithms are manufacturer-specific, how much more efficient would driving really be? It would seem like if all cars were operated by the same algorithm then you'd be able to build something that was more "ant colony" like that would similarly improve driving efficiency?
Even without higher-level coordination, independent autonomous agents on the road could still do a lot better than human drivers in at least two ways: a) the jam-busting behaviour described elsewhere on this thread could be built in, avoiding the counterproductive and unnecessary stop-and-go pattern that most human drivers seem to fall into, and b) even when traffic unavoidably comes to a standstill, a self-driving car could have near-instant reaction time on stopping and starting, meaning that the wave propagation would be much faster.
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.
I used to study ants;Diacamma sp. in India (not the pheromone laying one). These ants transport individuals through a method called tandem running.
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.
I feel like a significant portion of human traffic jams are caused by bottlenecks but as far as I can tell this was not addressed in the study. Would be interested to see how much more efficient ants are in the case where the width of the path is variable.
Nice and well thought out write up about the ant.
Ants are always busy and preoccupied fulfilling one task or the other.
Despite this, there is great team work and selflessness among the ants, which humanity can learn from and have a better society.
Well, anthropomorphism aside, ants kill and eat their peers if they detect damage or aberrant behavior. They behave as they do, because it is beneficial to the queen, whose future is the only one that matters.
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.