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Transportation

Your Car Will Tell You How To Hit the Next Green Light 364

Posted by Unknown Lamer
from the drive-better dept.
cartechboy (2660665) writes "Hitting that red light sucks. We've all been there, and you know what I'm talking about. But what if your car could tell you the ideal speed to maintain to hit the next green light? That's exactly what's going to happen in the near future thanks to car-to-car technology. Many automakers are already working on this new tech, and Honda's the latest to trial such systems. This is all part of what's known as Universal Traffic Management System which will eventually provide feedback on car-to-car and infrastructure systems before they go into practical use. The system will also be able to tell the driver if a red light is likely to show before reaching an intersection so the driver can slow down, or notify the driver when that red light will turn green. All of this may seem like something that's supposed to benefit the driver's temper, but in reality it's to help save fuel and lower emissions without any physical changes to the car. This is the future, and your vehicle will talk to other vehicles whether you like it or not."
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Your Car Will Tell You How To Hit the Next Green Light

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  • by Mr0bvious (968303) on Wednesday April 02, 2014 @09:53AM (#46638587)

    It doesn't spontaneously change the light - it puts a priority request to the traffic management system (which may or may not be granted depending on the system rules) and the signal change times are adjusted accordingly - any interfacing with the system would be able to be aware of this change to.

    This is actually no different than a pedestrian pressing the walk button to possibly change the sequence sooner.

    Disclaimer: I've worked on interfacing to some traffic control systems for providing priority through intersections to specific vehicles (GPS+GPRS+known route).

  • by mcrbids (148650) on Wednesday April 02, 2014 @10:11AM (#46638799) Journal

    Ha ha... paying attention goes oh so much deeper than countdown timers...

    What most people don't know is that you can improve your fuel economy rather dramatically using a variety of techniques commonly referred as "Hyper-miling". [wikipedia.org] I didn't think much of it myself until I got a car that has a fuel economy computer built into the dash, and then it started to click.

    See, brakes are death to fuel economy. Sounds obvious, but what isn't obvious is what that translates to in real world use.

    Example: negotiating a red light. Most people don't pay attention to red lights until they are half a block or so away. If it's red, they start to apply the brake, and then as the light stubbornly refuses to turn green, they apply more and more brake until they stop behind the next car. Which is exactly the *wrong* way to get best fuel economy. Instead, you should be looking ahead as far as possible, and apply the brake as early as possible to reduce speed as early as possible to increase the amount of time it takes to cover the block distance while losing as little forward momentum as possible. Instead of waiting until the last minute and losing all forward momentum, you brake early and keep perhaps 30 MPH. This means that you don't have to accelerate to 30 MPH and you save that much fuel.

    It was rather surprising to me how much difference I could accomplish using these techniques! On the freeway, if I drive around 50 MPH unless going up a hill, then more like 40-45, the normal 25-28ish MPG becomes closer to 34 MPG. Around the town, normally, my car (a 4-seat Chrysler convertible) gets around 18-20 MPG, but using these techniques about braking and reduced acceleration, I can get over 30 MPG on town surface streets! (flat land) Unfortunately, I do have to get used to being flipped off in order to achieve this.

    In any event, you *can* get a rather sharp increase in fuel economy by paying attention to the forces of momentum, timing and friction.

  • Re:Green wave (Score:3, Informative)

    by NikeHerc (694644) on Wednesday April 02, 2014 @10:12AM (#46638811)
    ... red lights are staggered so that you will have to stop at every single one of them...

    Around here, the traffic control idiots time lights so that you stop at every other traffic light. I've experimentally determined if you drive about 48mph in a 40mph zone, you'll rarely stop.

    OTOH, cops love speeders, so this is not an optimal solution. The optimal solution is to time lights so as to present as few red lights as possible, but people in government around here are generally complete losers.
  • by Anonymous Coward on Wednesday April 02, 2014 @10:16AM (#46638837)

    Err, no. Germany has red - red+yellow - green - yellow - red. No blinking involved. And yes, red-yellow means "get ready".
    Austria has the same plus flashing green before yellow.

  • So you're that guy who races up to red lights and then has to slam on the brakes.

    Here's what happens. You and I are stopped at a light with you in front of me. There's another light 20 seconds away at 35 mph or 10 seconds way at 70mph. The first light turns green and the second is due to turn green in 20 seconds. You arrive at the second light in 10 seconds and have to come to a complete stop. I arrive in 20 seconds the moment the second light turns green but I have to stop because of you. Everyone behind me also has to stop because of you. Your actions caused us all to decelerate and accelerate unnecessarily.

    Actually, I wouldn't stop. I'd slow down giving you enough room to accelerate so to minimize my change in speed, but most people wouldn't apply that forethought.

    The concept of aliasing is not applicable to the timing of traffic lights for a number of reasons. First, you're going the wrong way, a more reasonable answer would be 17.5 mph also works for lights timed for 35mph, but that's not true either. The timing is a phase variance, not a change in frequency. There's pretty much nothing you can do to beat the system of lights timed for a given speed other than drive that speed. That's a pretty optimal solution anyway.

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