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Light Traffic

senseable.mit.edu

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Re: Light Traffic

#91

Post by vinay427 »

mindslight wrote: post #66
zten wrote: post #11

Earlier quoted context omitted.

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.

Can you elaborate on where this is coming from? I know you're exaggerating, but in my limited experience I haven't noticed abnormally long yield times at intersections in southern California.

Re: Light Traffic

#92

Post by Cogito »

tomxor wrote: post #46
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…

> 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. I actually find roundabouts easier to navigate than large crossroads, I think this is partly because they actually…

This is exactly the question asked by myth busters.

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/

Re: Light Traffic

#93

Post by tedmiston »

jakecopp wrote: post #85
jakobegger wrote: post #69

Earlier quoted context omitted.

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.

You are right. I'm trying to say I think the problem is development bound and not insurmountable (secure, reliable, good fallback to timer) rather than "moving, storing, and processing data" bound as per the parent comment.

I agree with you that developing a prototype wouldn't be too hard. But actually rolling it out within a few cities (and getting cities to pay for it) are where I think the complexities lie. I think it's a social or bureaucratic problem more than a technical one.

Re: Light Traffic

#94

Post by notatoad »

closeparen wrote: post #83
mgbmtl wrote: post #37

I feel like so many similar proposals tend to ignore how saturated our roads are, how expensive the road infrastructure maintenance is, and how fast people expect to drive (because of long commutes from endless suburbs). 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…

Unsustainable compared to what? New York is clearly demonstrating that it’s incapable of sustaining a subway, and it has just about the best conditions possible for such a project. You think a place that can’t even manage roads can swing a subway? 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 p…

unsustainable is an absolute, not a relative. A road network doesn't have to be unsustainable relative to anything in order for it to be full to capacity at and for there to be no room for any more roads, which is the situation New York finds itself in. It is physically impossible for NYC to have sustained substantial growth to their private vehicle infrastructure, hence "unsustainable". If they want to grow their transportation network, they need to do it via other modes.

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.

Re: Light Traffic

#95

Post by tomxor »

rayiner wrote: post #80
tomxor wrote: post #46

Earlier quoted context omitted.

> 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. I actually find roundabouts easier to navigate than large crossroads, I think this is partly because they actually…

Roundabouts are not part of the driving test in DC. Indeed, roundabouts are so scary to Americans that most of the ones in DC have traffic lights. We also have roundabouts with roads cutting across them: https://ddot.dc.gov/sites/default/files/dc/sites/ddot/ward%2... .

hah, that is completely insane! the design completely looses all the benefits of it being a roundabout. Even those crazy triple mini roundabouts make more sense than that one.

Re: Light Traffic

#96

Post by zten »

mindslight wrote: post #66
zten wrote: post #11

Earlier quoted context omitted.

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.

The law as written means you have to yield on a bicycle in exactly the same way you would a car. There’s no room for China-level tolerances, as you describe.

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.

Re: Light Traffic

#97

Post by ramzyo »

Cool idea. This seems like a big caveat though,

>> 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.

Re: Light Traffic

#98

Post by revelation »

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…

It's a profoundly uninteresting result because, you know, we can already build autonomous trains. If you restrict the environment to what works for autonomous cars, we could have had them centuries ago. They will probably run on rails and look a lot like trains, but there you go..

Re: Light Traffic

#99

Post by jayd16 »

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…

>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.

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.

Re: Light Traffic

#100

Post by revelation »

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.

You got it the wrong way around. We only have lights and stop signs because of cars. They are a necessity for motor traffic, not bikes and pedestrians.

The flaw is strictly in the box that extends two more metres forward of the actual driver vision and all around offers terrible visibility.

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