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[–] 12 points 3 days ago (2 children)

isn't this already done by timing the lights based on distance and speed limit?

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  • [–] [S] 3 points 2 days ago* (last edited 2 days ago)

    I think so. I'm realizing the article is actually very confusing.

    https://katu.com/news/local/speeding-in-portland-some-of-the-city-traffic-lights-are-designed-to-stop-you-speed-rest-red-light

    Since 2024, the Portland Bureau of Transportation (PBOT) has used “Rest in Red” technology along Powell Boulevard between Southeast 21st and 33rd avenues. The system uses sensors to detect approaching vehicles. Drivers traveling at or below the speed limit receive a green light, while speeding drivers face a red light.

    The system operates only at night.


    https://www.portland.gov/transportation/vision-zero/rest-red#toc-rest-in-red-explained

    Traffic signals with “rest in red” technology can display red lights in all directions during late night and early morning hours when traffic volume is light rather than cycling through green, yellow, and red the way they do normally during the day.

    When a person driving a vehicle approaches a “rest in red” intersection, the traffic signal may stay red until it detects that the driver reached the intersection. Assuming no cross-traffic is approaching, the traffic signal will turn green to benefit people that are driving within the speed limit.


    Other traffic signal technology examples

    PBOT uses other types of traffic signal technology to encourage safe travel speeds. For example, if a person drives 13.5 mph downtown, they are more likely to catch green lights and travel in groups with other vehicle traffic.

    Similarly, PBOT has deployed special signal timing along N Vancouver Avenue so people biking don’t repeatedly get stopped by red lights.


    How the technology works

    Detection

    At most traffic signals, PBOT uses smart sensors to detect approaching cars to determine when to give a green light. PBOT currently uses "microwave detection" mounted on traffic signal mast arms. "Microwave detection" can locate approaching traffic from several hundred feet away.

    Signal controllers

    Signal controllers are the "brains" of the traffic signal that make "rest in red" work. During peak hours, signal controllers collect and communicate important information. During off-peak hours, signal controllers with the right detection can allow for different types of operation to minimize speeding.

    Newer traffic signals are more likely to include smart detection technology and upgraded signal controllers. However, many traffic signals across the city are aging out and have limited or no detection as well as signal controllers which haven’t been upgraded.

    PBOT plans to update traffic signals as needed and funding becomes available to match city policy.

    Still confusing, but I think they're implementing both, over time.
    Supposedly Oregn State University is or will be conducting research on its effectiveness in reducing crashss, but I couldn't find any info from them. Maybe that will clear things up.

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  • [–] 1 point 3 days ago

    It's hard to do correctly in a lot of cases. At least to the point where people going 10mph over don't go a further 10mph more. Although in most cases it's just idiots at city traffic management who can't do math.

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  • [–] 17 points 4 days ago* (1 child)

    Aint the surveillance state s'wonderful?

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  • [–] 26 points 4 days ago* (3 children)

    Seriously, also aren't lights supposed to be programmed to move the most traffic throughout the day... Why would people want to make it less efficient.

    Edit: went back and watched the video. They aren't giving preferred treatment to anyone, they just timed the lights so if you go from 1 to the next it should turn green based on speed/distance. I'm not really sure why you would even need the speed sensors, you can just measure the distance and set them..

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  • [–] 4 points 1 day ago* (last edited 1 day ago)

    Why would people want to make it less efficient.

    Slower speeds are more efficient.

    This is because at higher speeds, far more safety distance is needed. Because it is dominated by the braking distance, the safety distance increases roughly quadratic with speed. The transport capacity of a steet is however defined by speed divided by safety distance times its lanes. Which means that at higher speed, fewer vehicles per second can pass a point. And small, slow city streets can easily, and safely, transport more vehicles per second than a highway.

    That's also why at an airport, a plane needs a runway with kilometers of free space for a single plane. It is the speed, which requires lots and lots of longitudinal space to retain safe control.

    And this is also why bike paths can generally transport far more vehicles per second than streets for cars. For example, Copenhagen has a bicycle bridge that spans the harbour, which is called Cykelslangen. It has only two lanes, and at rush hour times, it transports over two vehicles per second.

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  • [–] [S] 2 points 3 days ago

    I had thought this too, but in the article they mentioned speed sensors that track the speeds of vehicles in one (maybe two?) of these cities. So I think it's a mix of both of those things, with them probably preferring the preferential approach.

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  • [–] 10 points 3 days ago* (last edited 3 days ago) (1 child)

    So they do sync it up to make me hit every single red light if I'm running late for work in the morning and speeding! /s

    I bet it would be hard being a paranoid schizophrenic right now in this surveillance state that's being manufactured.

    Or maybe its liberating since it would all be true "See, I told you the television was listening to our conversations! Here's an article about it in The NYT"

    Wait until these kind of metrics of "rewardable" and "punishable" drivers shows up on your car insurance rates.

    There's always a dollar to be made with all this data they are harvesting and this is just a small beginning of a series of steps that are playing out far faster than I had ever dreamed they would.

    Edit: you know I just thought about how it said begins rewarding drivers. That means they had to test this out for at the very least several months of getting all the data of "bad" and "good" drivers.

    I seriously wonder what else they've tested out like that with traffic and whatnot. Mixed in with the surveillance in new vehicles 2027 and onward and this is going to get pretty wild

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  • [–] 10 points 3 days ago* (last edited 3 days ago)

    There's too frequently a mismatch between the speed communicated by road design, versus that dictated by a sign. Mechanisms like this overwrite the driver's intuition, which can only lead to more frustration. Sure, there are incompetent drivers on the road, but that doesn't mean you have to micromanage the fleet in its entirety. There's plenty that have a functional brain and are more than competent enough to assess a given situation, irrespective of what a fixed speed limit might indicate. And if drivers used to speed to catch green, that indicates to me the waiting cycles must not have been optimized; and doing so possibly yielding the same result.

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