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Light Traffic

senseable.mit.edu

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Re: Light Traffic

#61

Post by enobrev »

jakecopp wrote: post #57
maxander wrote: post #41

So a system that requires all vehicles on the road to have flawless sensor and communications systems can achieve some improvement over current-day technology (from the paper, approximately a "doubling of capacity" for intersections with this implemented.) 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 order…

What I don't understand is why every traffic light doesn't have cameras and some image recognition/machine learning (whether local or remote) to improve the timing - it would be such a cheap and easy fix compared to putting a sensor in each car.

Government owned cameras at every intersection doing [anything] recognition sounds horrible.

Re: Light Traffic

#62

Post by craftyguy »

tinco wrote: post #30
seanmcdirmid wrote: post #28

Earlier quoted context omitted.

You mean in the USA. In a cyclist-friendly country like the Netherlands, it is considered completely normal even by pedestrians.

That it is normal doesn't mean it's not pedestrian hostile. I catch myself cycling over-aggressively. For example, everyone knows that pedestrians have right of way on a zebra-crossing. Good luck with that in The Netherlands. Cyclists will simply not give you right of way, they'll swerve around you, ignore you, and generally make you uncomfortable. The Netherlands is a cyclists country in much the same way as the U.S…

Interestingly enough, right of way for ships/boats in waterways tends to favor the largest/heaviest over the smallest/lightest. It's oftentimes more dangerous for a larger thing to take evasive action than a smaller thing. I think this should carry over to vehicle/pedestrian right-of-way laws. Pedestrians should assume responsibility for their safety and pay attention (including taking evasive action), just as cyclists should do the same in the presence of cars, and cars should in the presence of semi-trucks, etc. I think that's what you are seeing in The Netherlands. Based on my travels in Europe and Asia, it seems a good portion of the world follows this model, and it's the US that is different.

Re: Light Traffic

#63

Post by craftyguy »

YSFEJ4SWJUVU6 wrote: post #44
tinco wrote: post #30

Earlier quoted context omitted.

That it is normal doesn't mean it's not pedestrian hostile. I catch myself cycling over-aggressively. For example, everyone knows that pedestrians have right of way on a zebra-crossing. Good luck with that in The Netherlands. Cyclists will simply not give you right of way, they'll swerve around you, ignore you, and generally make you uncomfortable. The Netherlands is a cyclists country in much the same way as the U.S…

I've always thought the reason many cyclists treat red lights and stop signs mere warnings instead of rules is because it's annoying to have to speed up from standstill with your own power. IMO it's a flaw in human-powered vehicles, although some purists will certainly vehemently disagree such a thing can even exist.

As a cyclist myself, I would never run a red light or stop sign, and I have a history of shouting at fellow cyclists that do. Running traffic signals is an utterly stupid thing for a cyclist to do.

Re: Light Traffic

#64

Post by jakecopp »

tedmiston wrote: post #60
jakecopp wrote: post #57

Earlier quoted context omitted.

What I don't understand is why every traffic light doesn't have cameras and some image recognition/machine learning (whether local or remote) to improve the timing - it would be such a cheap and easy fix compared to putting a sensor in each car.

A sensor itself isn't expensive but moving, storing, and processing all of that data to ultimately take action is. Let alone concerns with people about being recorded in public, even if red light cameras are permitted in some states today.

Even OpenCV running on a Raspberry Pi can pick out cars in a moving image - a bad offline solution (with a sensible fallback) would be better than a timer.

On a large remote setup I think you are right though.

Re: Light Traffic

#65

Post by jakobegger »

jakecopp wrote: post #57
maxander wrote: post #41

So a system that requires all vehicles on the road to have flawless sensor and communications systems can achieve some improvement over current-day technology (from the paper, approximately a "doubling of capacity" for intersections with this implemented.) 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 order…

What I don't understand is why every traffic light doesn't have cameras and some image recognition/machine learning (whether local or remote) to improve the timing - it would be such a cheap and easy fix compared to putting a sensor in each car.

Lots of traffic lights in my area already have sensors (induction loops to detect waiting cars or approaching bicycles, IR motion detectors to detect pedestrians). In some cases this is really useful (eg. a traffic light for a bike path does not need to switch very often in winter, so it only switches when a bike approaches)

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.

Re: Light Traffic

#66

Post by mindslight »

zten wrote: post #11
seanmcdirmid wrote: post #6

Earlier quoted context omitted.

It is kind of funny because pedestrian crossings already kind of work like this in China. The car will never ever stop for you, rather, it will adjust its speed and swerve slightly to avoid a collision (if expected, if unexpected, then its a totally different game). Likewise, the pedestrian is expected to move in a consistent direction and adjust their speed to avoid being in the way of a car. The result is that car…

Oddly, this is a cyclist behavior that is very widely admonished as being pedestrian-hostile.

"Widely" ? Maybe in altruism-display places like SoCal, where the expectation for traffic interaction is to stop and have a ten minute meeting about how to proceed so everyone can feel leave feeling superior.

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.

Re: Light Traffic

#67

Post by ZenoArrow »

tomxor wrote: post #35
ZenoArrow wrote: post #19

What are the benefits of this proposal when compared to roundabouts?

I live in the UK where roundabouts are almost everywhere. While they are definitely more efficient than crossroads they still have some flow control issues in some scenarios: each joining road effectively controls the flow of the next joining road further along the roundabout through priority, this is both a strength (automatic flow control) and a weakness (unbalanced flow of joining roads): Imagine a simple roundabo…

I also live in the UK, so I'm familiar with roundabouts for the same reasons you are, but I'm glad you've given the explanation for those that are not.

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.

Re: Light Traffic

#68

Post by Reason077 »

jakecopp wrote: post #57
maxander wrote: post #41

So a system that requires all vehicles on the road to have flawless sensor and communications systems can achieve some improvement over current-day technology (from the paper, approximately a "doubling of capacity" for intersections with this implemented.) 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 order…

What I don't understand is why every traffic light doesn't have cameras and some image recognition/machine learning (whether local or remote) to improve the timing - it would be such a cheap and easy fix compared to putting a sensor in each car.

Many traffic lights do have cameras/sensors to detect waiting traffic and measure wait times.

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.

Re: Light Traffic

#69

Post by jakobegger »

jakecopp wrote: post #64
tedmiston wrote: post #60

Earlier quoted context omitted.

A sensor itself isn't expensive but moving, storing, and processing all of that data to ultimately take action is. Let alone concerns with people about being recorded in public, even if red light cameras are permitted in some states today.

Even OpenCV running on a Raspberry Pi can pick out cars in a moving image - a bad offline solution (with a sensible fallback) would be better than a timer. On a large remote setup I think you are right though.

OpenCV on a Raspberry does not sound like something that is reliable and easy to deploy.

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.

Re: Light Traffic

#70

Post by chrisper »

rcarmo wrote: post #14

There's been a marked tendency to replace intersections with roundabouts and shared spaces ( https://en.wikipedia.org/wiki/Shared_space ) in many places, including the outskirts of Lisbon (as well as a few legendary mazes in Britain). 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 wi…

I don't think roundabouts would work in the Bay area because it requires that people know how to use turn signals.
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