Light Traffic
senseable.mit.edu
senseable.mit.edu
This is a profoundly uninteresting result, given the current-day technology in question is "a dozen lights attached to a timer." Add devices that are several orders of magnitude more expensive and yeah you'll get something better- that they only achieve a factor of two improvement (in theory!) reads as a stunning failure of autonomous vehicle technology to pull their weight in this regard. (Granted, more clever schemes might be produced that might get better results from this scenario- it's hard to prove that they can't be effective.)
Better idea- instead of having the world pay for sensor/communication systems on every car, have the same sensor packages installed on the traffic lights so that they can operate in a smarter fashion. Orders of magnitude less expensive, and quite possibly as effective in reducing traffic backup.
Let alone concerns with people about being recorded in public, even if red light cameras are permitted in some states today.
On a large remote setup I think you are right though.
It‘s a long way to go from something that you hack together in the living room to something you can deploy on hundreds of traffic lights, that works in every weather, that can easily be configured for different use cases, and that can be serviced by the technicians.
A Raspberry Pi is a surprisingly useful and cost effective device when it comes to IOT. Most industrially hardened devices of similar capacity cost a bit north of an order of magnitude more.
There are really only a couple of things that would need to be addressed, a good weather-tight case that allowed for heat dissipation, decent storage (most microSD has a short lifespan), and a good 5v power supply.
In many cases, designing a system that is cheap, expendable, and expected to fail is way less costly than the alternative.
Yes, you can make the software deployment go easier, and resin looks like an interesting project from that front. But that really is only a small part of the problen, and those hardware problems you described aren't trivial. The testing you described to convincingly show that your device can handle the environmental requirements isn't trivial. (And by environmental, I dont just mean weather, but also things like available power quality, vibration, etc.)
These industrial devices aren't expensive just because the suppliers aren't aware of RasPi, or are looking to gouge you. Its because they put in a lot of work to qualify these devices for their intended conditions. The RasPi, hacked up solution might actually be the WAY more expensive option over it's lifetime, if I have to roll maintenance crews every couple of months to replace SD cards or fix a flaky connector. And god forbid our code hangs in a way that makes all of the lights at an intersection green. "Oh you have a way to prevent that? Prove it." Designed to fail works fine for microservices where I can spin up a new instance rapidly, but it isn't the best match for industrial or infrastructure in most cases.
Apologies if I'm coming across overly snarky here. I genuinely love the RaspPi, and its got a great niche for prototyping, hacking up one-off projects, or even as the base for many types of connected projects. But I've also worked on industrial and infrastructure types of systems, and more than once I've seen someone say that they've got a cheaper solution to X, when really they've got something that may look cheaper if your only looking at upfront costs, but they are completely ignoring the lifetime costs of the solution.
I do some IIoT stuff, so I have a little experience here. Many of the lower cost PLCs and industrial edge devices have no better environmental characteristics than a Raspberry Pi. They just happen to be more expensive by comparison because they're competing in a market with much more expensive devices. In many cases, as you suggested, buying those devices is a false economy.
My point is simply that they're not that bad, and like you said, one should truly consider the lifecycle costs.
Meanwhile, if conversation involves a plausible future where all/most vehicles (inevitably including police cars and other government-owned vehicles) are autonomous and have the same kind of sensors, its hard to imagine the anti-surveillance angle being a decisive factor. I'm not for pervasive surveillance, and perhaps the NSA will be nice and claim really convincingly that they can't access records from traffic lights... but that bird has flown, anyway.
I think that the problem is that often there is too much traffic from all directions and even with all the sensors in the world the traffic light can‘t change that.
It's not always quite so simple as using ML to adjust light timing, however. In big cities, at least, traffic lights are sometimes deliberately intended to slow traffic down in order to reduce volumes and speeds on the street, or to reduce congestion elsewhere on connecting roads.
Missouri Department of Transportation's St Louis District has one of the best FAQs [1] on this tech that shows how these cameras work: exactly as you'd suspect from some OpenCV proof-of-concept.
The cameras are a more robust replacement of the in-pavement induction loops, which are much more widely deployed, but give you a subset of the information at a higher cost.
https://en.wikipedia.org/wiki/Sydney_Coordinated_Adaptive_Tr...
That being said, I had some interesting conversations with a person who worked for Transport for NSW who said some of the signalling backend was recently improved to streamline future integration with self driving cars, I can't find a reference for this though.
[1] http://www.nyc.gov/html/dot/html/pr2012/pr12_25.shtml
[2] https://en.wikipedia.org/wiki/Sydney_Coordinated_Adaptive_Tr...
Sounds like a profoundly interesting result to me -- strong evidence that we'd need to look elsewhere to increase transit carrying capacity. Maybe AI cars can't reduce traffic that much afterall.
Human drivers preclude such a system. The article actually is about replacing the intersection but you still need the self driving cars to actually perform the optimizations.
It will take time to iterate to get to the 4x-10x improvements we all hope to see.
There was even a BBC report on the latter (which I can't find right now, as usual, only a follow-up: http://www.bbc.com/news/uk-33303031).
Drawing a (admittedly inaccurate) parallel with shared spaces (which are harder to navigate by sensory deprived humans than standard intersections), I'd say roundabouts (which preserve crossings) would be a more sensible short-term approach overall -- especially considering the remaining human drivers.
Full disclosure: I don't drive anymore. Gave it up decades ago because I prefer to do something useful with my commute times, and resort to public transportation or Uber whenever possible, which (ironically) allows me to arrive earlier to meetings than most of my colleagues (who need to hunt down a parking space).
> Hans Monderman and others have suggested that, by creating a greater sense of uncertainty and making it unclear who has priority, drivers will reduce their speed, in turn reducing the dominance of vehicles, reducing road casualty rates, and improving safety for other road users.
clearly, Hans Monderman has never driven in Mumbai, India.
But for modest to high volume traffic, roundabouts are better (although if the traffic flow is constant, you usually have to place the crossings a bit further away from the center of the roundabout, which makes it a little harder on elderly pedestrians to go fully "across" since they have to walk the extra distance).
It does work incredibly well and there are rarely any accidents. The downside however is that it's quite a struggle to cross. It makes me dread to leave the ferry and enter the warzone once again every morning. I understand that it is designed to make me uncomfortable, but it is taken to such an extend that I don't even really want to walk there.
You mean, no cars?
https://en.wikipedia.org/wiki/High_Five_Interchange
That crosses 16 lanes with 14 lanes. (3,5,5,3 with 3,4,4,3)
Or Naples, Italy.
I'm reminded of my time in Berkeley. Now, in spite of what Fox News might tell you, Berkeley is one of the most ridiculously upper class places possible. But, it's right next to Oakland, a place that... isn't.
In Berkeley? If you even look like you were about to step out into the road in the middle of the street, people would stop for you. Over in El Cerrito or Oakland? you could be in the crosswalk, and nobody even slows down.
https://www.theguardian.com/cities/2016/may/17/superblocks-r...
I actually find roundabouts easier to navigate than large crossroads, I think this is partly because they actually are objectively easier and safer to navigate (one stream of traffic) and partly (but mostly) because they are dominant in the UK.
But for the same reason (familiarity) I expect many in the US would find roundabouts hard to navigate (and maybe unsafe as a result?), it's more about what you are used to and what you had to learn as part of your driving test.
Are roundabouts part of driving tests in the US?
Personally, I freak out when I see a roundabout coming up, and slow down dramatically. Or, I completely avoid them.
[0] https://www.citylab.com/transportation/2016/03/america-traff...
You can see the segment here[0]
They measured throughput for both 4-way stops and roundabouts, with both people who hadn’t used them before and people who had.
Unsurprisingly (for me at least) roundabouts were significantly better, even for people unfamiliar with them.
0: https://m.wimp.com/mythbusters-four-way-stop-vs-roundabout/
People will learn to use turn signals quickly if they are fined.
Works well in Europe. Though I can understand why this wouldn't work in the US.
In my experience they keep traffic moving really well, as long as the traffic load into each entrance is roughly equal - otherwise it's hard to enter the roundabout from a lesser used entrance.
They take up more space than traffic lights in most situations, however Canberra is a planned suburbia so that wasn't an issue there.
[1]: http://www.abc.net.au/news/specials/curious-canberra/2016-12...
Of course, it often doesn't work, and it is only possible at all given the slower vehicle speeds of a congested road network. Also, the flow of pedestrians in China is rather more continuous than in America.
The Netherlands is a cyclists country in much the same way as the U.S. is car country, pedestrians are second class.
IMO it's a flaw in human-powered vehicles, although some purists will certainly vehemently disagree such a thing can even exist.
I definitely get not wanting to stop, and I'll try and optimize. For example in Amsterdam there's traffic lights with counters, and as a cyclist you can usually safely go when there's 5 seconds left, but I don't count that as ignoring the traffic light.
Cutting a red light into slow traffic would be very rude.. I don't think that happens a lot here.
The flaw is strictly in the box that extends two more metres forward of the actual driver vision and all around offers terrible visibility.
In general it's just called yielding, and that it happens in all four dimensions is implicit. The difference in China is that the tolerances are smaller.
People may also be picturing different scenarios: NYC couriers and delivery people swerving around them inspires scorn, as do cars driving around you at 30mph in a crosswalk even if no contact will be made. Edit: but the former scenario should happen more often than the latter simply because the car is often too big to pull the same stunt without actually causing physical injury.
I love the picture of a 10 minute traffic meeting, though.
This hasn't been my experience. At least twice in the last 7 years, a car has stopped when about to do a right-on-red, to allow me to cross. Sure, that's 0.01% of the time, but not never :)
"The car will ... will adjust its speed and swerve slightly to avoid a collision"
This also does not match my experience. Whether or not I make eye contact with a driver, it's very rare that they make enough of an adjustment to their speed or direction to avoid a collision. I always have to stop, or adjust my speed+/direction.
As for (b), it only counts if traffic is going slow enough, and it should be part of a human wave. Otherwise, it is a bit like a game of frogger.
Yes, like a game of frogger.
Maybe the intersection looks like this once you add pedestrians and cyclists: https://vimeo.com/106226560
Edit: also worth checking the earlier discussion from a couple years ago: https://news.ycombinator.com/item?id=11336009
We need to find innovative ways to implement forms of collective transportation (rail or what not) in already dense areas. Rail/subways have already proven how effective they are. Autonomous vehicles are necessary to improve road safety, maybe they can help slightly reduce the amount space used by roads, but they won't solve most of the problems we have today on our unsustainable roads.
Is it sustainable to all move closer together? Not if the residents of existing cities have anything to say about how those cities are governed. They don’t want the extra population.
And i reject your assertion that New York has the best possible conditions for transportation infrastructure. A lack of space, a huge demand, and a corrupt mixture of local government and unions don't make for an idea development environment.
High density and high transportation demand are prerequisites for having a public transit system at all. And what dense US city's government isn't corrupt or incompetent?
As long as roads continue to exist in any form, it seems crazy not to aim for efficiency. What is to be gained by passing up opportunities to make them efficient?
So this is not a wrong metric, it is just that both metrics need to be taken into account.
I know someone will bring up "well, traditional car will fail and results in fatal crash too, but technology can help us catch that and predict accidents by looking at 360 degree!". True, but let's not let that promise blinds us.
Also, this senor-led, slot-based system won't work in areas like NYC midtown, so not a one-size fits all solution (that's a given). If we exclude accidents and roadworks, then traffic lights, narrow roads, increase of cars on the road (due to ride-sharing and cars becoming more affordable), and double parking, they all contribute to the majority of traffic jam.
Some futuristic fixes include flying cars, roads in mid-air, roads through buildings, and more underpass might help but they don't scale when you keep adding more cars.
We need to improve our mass transit. If you have ever played Skyline or SimCity, you know that intersection sucks and mass transit is preferred over roads. Too many school buses will slow down traffic. Multi-lane to single-lane can jam the road. The NY subway system coverage is pretty good, but each train runs on one lane and is a single point of failure. Kudos to those working in transportation planning though...
“Without tunnels we’ll be in traffic hell forever” -Elon Musk
"Despite simulation-based evidence of the potential benefits of SIs [Slot-based Intersections], a comprehensive, analytical framework to compare their relative performance with traffic lights is still lacking. Here, we develop such a framework."
A handful of other quotes from the body examine the rationale and context for investigating this question.
They compare the results of a platooning-type control strategy with a fair scheduling strategy, and the "usual", fixed-cycle strategy, and find that the platooning one, deemed 'BATCH', scales towards the optimal throughput as the number of vehicles increases. There's formulas and graphs to back this up.
This is good work, but the website is a marvellous example of marketing; subtly promoting the higher implications of the work instead of the work itself.
[1] http://senseable.mit.edu/papers/pdf/20160316_Tachet_etal_Rev...
My lingering question after reading the paper is the enforcement mechanism. Process scheduling because there's an omnipotent authority with total control over all processes but whatever system is used needs to work with no central control and if all the cars are programmed to be selfish.
>> With today's traffic volumes, queues would vanish and travel delays would be cut to almost zero.
I’m pretty sure it’s critical in traffic engineering to consider how the design would hold up in the event of larger volume given greater efficiency. There’s a single lane exit on the Mass Pike about 5 miles outside of Boston that’s always backed up onto the highway. I’d always wondered why they hadn’t added a lane, put a divider, or otherwise designed the exit differently. A few years ago a former colleague met the engineer who did the traffic analysis for that exit. Apparently adding capacity to achieve greater throughput would’ve resulted in worse traffic at the exit. According to the models they developed, the more constrained solution was actually optimal, although to the frustrated driver (me!) it still seems poorly designed.
Granted, this is an example of increasing capacity rather than improving efficiency. Regardless, I’d be interested to see how the MIT solution holds up to increased traffic volume.
So it seems like they should be trying to amortize that cost by grouping cars together, both horizontally (side by side) and vertically (front to back).
So in other words, have a cluster of, say, 5 or 10 cars that cross the intersection together.
That can be done by adjusting the speed of cars well in advance of the intersection to group them, so it's not necessary to come to a stop as with stoplights.
As a result we have traffic lights on roundabouts as well sometimes, which prevents this unfairness but also takes them back closer to the efficiency of a crossroad.
I think the best combinations would be autonomous + roundabouts, I think fast crossroads are just dangerous (autonomous or not). Roundabouts force vehicles to slow down due to the forced turn and negotiate one stream of traffic going in one direction rather than two streams going in up to 4 directions at speed. The potential injury from the later is so much higher it's a non-argument.
In your example, "an crossroad with 4 joining roads, if only two joining roads next to each other are active and of those two, the one to the right has an endless contiguous flow, then all traffic on the road to the left is blocked", this is a theoretical weakness, but in practice it rarely occurs. For starters, the chances of zero traffic from the other two roads is small, and "continuous" traffic is rarely busy to the level where cars from the road to the left are blocked completely.
Furthermore, if such bottlenecks occur, they can be mitigated against by diverting traffic, through the addition of changes to surrounding roads.
Roundabouts may not be something to be implemented without consideration to the surrounding road infrastructure, but they seem like they would be decent step forward for many busy intersections with traffic coming from multiple directions.
It seems right now like we’re really close with self-driving cars but objectively flying ones would be a lot better:
Shorter distances to travel (point to point), easier to implement collision avoidance, faster, no need for this crazy infrastructure we build/maintain of roads, bridges, traffic lights, tunnels, snow plows, street cleaners, etc...
1. Roundabouts are safer and better with human drivers but bad from a usability standpoint. It's annoying to drive, slower, and makes people feel nauseous when driving through many. When we have road usage of autonomous vehicles surpassing 50%, I suggest to remove them.
2. Two-Leveled intersections without left turns seem cost effective and highly advantageous in cities. To lower the cost even further, it may be possible to design them for vehicles only (much lower ceilings needed, so much lower cost). Left turns can be achieved (especially in the US this is viable) bu going right three times (going around the block). Two-leveled intersections without left turns can reach 100% capacity in all lanes from all directions.
3. Lane-specific traffic light already may increase efficiency on intersections. Imagine a 2x2 intersection from both directions: the right turns can be green (where cars turn right on the rightmost lane) while through-traffic can use the left lane.
You're watching it wrong: It's a dystopian future in which all humans died out after years of being forced to take part in a city scale version of frogit with perma-death against autonomous vehicles.
My city put bridges over a lot of the major roads for people to cross. A few roads have a tunnels underneath as well.