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Right turn on red law gasoline & pollution savings.

Discussion in 'Gen 2 Prius Fuel Economy' started by prius04, Oct 10, 2004.

  1. prius04

    prius04 New Member

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    Back in the Carter administration the US passed the "OK to turn right at a red light after full stop" law.

    This was done to save millions of gallons of gas and tons of pollution emisions. Some say it was also done to lower the over supply of pedestrians, but that's another story.

    I wanted to do some calculations and estimate the savings if every car and truck in the world had a mini hybrid modification that would shut off the car's engine at stop signs and red lights and in bumper to bumper traffic. This is the only thing the mod would do so it really would not be a hybrid. I think the GM siverado is going to have this on it next year.

    Now it's been said that the Prius is about $3000 more just because of it's HSD. So I figured a larger generator/starter with a larger battery should cost no more than $800 or so per car in the USA.

    Then I was going to calculate how much this simple mod would save. It seems to me that this mod would probably pay for itself in 5 years or so. And by stretching out our oil supply, it would probably save us even more.

    So I did a Google search to try to find some data on how much this "right turn" law saves us. Then I'd take that data and extrapolate it somehow to figure out for all stops. But I could not find any data to start with.

    Anyone have info on how I might start to make this rough calculation?
     
  2. DaveinOlyWA

    DaveinOlyWA 3rd Time was Solariffic!!

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    well here in WA st, it is also legal to make a left turn onto a one way street on red. however, not many people know about this law as is evidenced by the myriad of paired one way streets we have here. i cant tell you how many times i would be stuck behind someone at the light waiting to turn left and there is no traffic coming and they sit there waiting for the light because they do not know the law... very very irritating.
     
  3. bruceha_2000

    bruceha_2000 Senior Member

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    It was legal when I got my driver's license in CA - 1972. VT must be a bit slow on the uptake as it wasn't legal when I moved here in 1979 but was soon after. Must have been the Carter initiative that pushed them over the edge :)
     
  4. prius04

    prius04 New Member

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    During the first energy crisis, this law passed and all states were required to honor it or lose federal highway money.

    If a state or municipality wanted to block it, they had to put up signs at each intersection.

    I remember back then that some cities that were against the law proceeded to put up signs barring it at every stop light intersection in the city. Boston was one of those cities.

    As for left turn on red after stop, I've heard about such laws but as far as I know, that law has not been nationalized.


    By the way, this right turn law (from what I read while trying to find out how much fuel it supposedly saved) specifically says that motorists are not FORCED to go after they stop. The law allows them to sit if they want. But if you continued to sit after the light changed green, they do have laws against that. Laws like "blocking the flow of traffic".

    So if you are stuck behind someone under those circumstances, they are apparently within their rights. I thought that was an interesting wrinkle to that law and I never knew that before.
     
  5. TonyPSchaefer

    TonyPSchaefer Your Friendly Moderator
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    Prius04, I think you will find it very difficult to do the math. When I think about it, I'm bogged down by the varying lengths of stoplights, the varying traffic patterns determining if the cars can go or not, and the number of cars at each light. It's the number of cars at the lights that make it interesting. When the first one goes, the others will kick in their engines to move forward. Then they will stop and their engines shut down. As each car goes, the entire line will witness engine shut-off and kick-in multiple times. This is the advantage - of course - of the fully hybrid system: the ability to operate on pure battery power when creeping. I'm not trying to rain on the parade of doing the math, just making some points.

    As for the turning on red laws: I was always told that it's legal to turn on red as long as you have a "window of safe opportunity" and you are not crossing a lane of opposing traffic to get to your destination lane (or something like that). This incorporates the left turn on red FROM the left lane of a one-way street ONTO the left lane of a one-way street. However, you can not turn left onto a one-way from a two-way street because you will have to cross the other lane and possibly the path of someone turning left off the one-way in front of you. (I would try to convert that for the international drivers, but it would confuse us all.)

    It's the "window of safe opportunity" that really drives me crazy. Call me cautious, but unlike many drivers around the Chicagoland area, I will not pull out directly in front of an oncoming car. In fact, I've been honked at because I have not ventured into the direct path of traffic. So stop honking at me Dave, it's my legal right to sit there if I feel like it! :)
     
  6. prius04

    prius04 New Member

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    Thanks Tony. And I agree that any calculation would be filled with so many variables as to make it suspect.

    That's why I hoped to start with the data that I know is already out there regarding right turn on red. I figured that that data must control for all the variances in length of red lights and what not.

    Once I had that data, I could make a guess on how many cars go straight at a red light versus those that go right. Maybe 80% go straight? It's probably higher but I would want to be conservative with any calculations.

    Then I'd simply due some algebra like 80(%) is to x like 20(%) is to the # of gallons saved by the right on red law.

    This calculation would give me a very raw figure on the savings that a shut off system might provide.

    Then I would take that figure and try to figure out how much each car might save per year. Then I would compare that figure to see how long it would take to get to $800. $800 is my guess on what this simple shut off system might cost per car once mass production kicks in. I base this upon the supposed $3000 that the HSD system cost Toyota. (I happen to think it costs Toyota a lot more than that, but I only have my gut on that one.)

    And I very much agree that starting and stopping during traffic creep is one of the advantages of a full hybrid. But I'm making some assumptions that getting the entire auto market to go full hybrid at a 3 to 5 grand premium per car is just too optimistic. But getting them to pay $800 just might be doable and it would get people used to the technology. It just might be a way to get the job done in an evolutionary way rather than a revolutionary way.

    My take on the value of the Prius is not so much in what the Prius can do now, it's where the Prius technology will take us in the next 10 years. I fully intend to keep my Prius for 10+ years. But it just may happen that the 2008 Prius gets 200 MPG with solar collectors and a home wind station. And if that happens, I may not keep my Prius for that 10.
     
  7. DaveinOlyWA

    DaveinOlyWA 3rd Time was Solariffic!!

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    in the state of Washington it is not your legal right to sit there if you want to.

    any attempts to unreasonably impede an efficient flow of traffic is a ticketable offense.
     
  8. prius04

    prius04 New Member

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    I pointed out in one of my posts above that you can get a ticket for impeding the flow of traffic.

    But as I said before, this right on red law came from the federal government back in the 1970's. States were required to pass this law to continue to collect federal highway money. And THAT law that was passed way back then specifically allowed people to NOT go on right after stop. The law specificaly overuled any "impeding the flow" citation.

    And the only reason I know this is because I found it in numerous places when I tried a google search looking for the gasoline savings from the law. I simply added that tidbit to one of my posts above because I thought it was an interesting wrinkle.

    Now that original law may all be moot today and your state may indeed require people to take that turn after a stop, or run the risk of a ticket. I have no way to find that out. If you say so then so be it.
     
  9. DaveinOlyWA

    DaveinOlyWA 3rd Time was Solariffic!!

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    it is so... but no one will get a ticket for it. the law says that you must verify that you have enough clearance to enter the lane of travel.

    it wouldnt be worth it to take someone to court to prove that they had enough clearance.