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Cut to speed limit might be on the cards.

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  • Registered Users Posts: 5,704 ✭✭✭ TheRiverman


    I have no problem with that, I have been doing economy driving for many years, and I am not a nuisance on the roads doing it.



  • Registered Users Posts: 5,704 ✭✭✭ TheRiverman


    I detest the Greens, but this happened previously before they existed. In 1979 the 60 mph limit was reduced to 55mph to save fuel during the oil crisis back then.



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  • Registered Users Posts: 11,929 ✭✭✭✭ elperello


    This applies to all fuels.

    If you burn less you save money.

    If the fuel gets more expensive you save even more money.



  • Registered Users Posts: 24,848 ✭✭✭✭ Wishbone Ash


    The reduction of the speed limit from 60 to 55 was in the US as far as I can recall. I don't remember it being done here but I'm open to correction.

    You seem to think it's a bad thing which is puzzling.



  • Moderators, Business & Finance Moderators, Motoring & Transport Moderators, Society & Culture Moderators Posts: 63,170 Mod ✭✭✭✭ L1011


    It was.

    The ROTR until the mid/late 1990s insisted NSL was still 55, even though it was restored in about 1990.



  • Registered Users Posts: 5,615 ✭✭✭ jd




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  • Moderators, Business & Finance Moderators, Motoring & Transport Moderators, Society & Culture Moderators Posts: 63,170 Mod ✭✭✭✭ L1011


    Amazing how those changes too until 2005 to come through with metric - the 55mph to 60mph was actually 1992 looking up the SI.

    That 50mph for HGVs was also brought in in 1992, but was still less than 56mph on motorways that equivalent vehicles were allowed do in the UK, and it was ~2013 before we changed to that (90km/h by then)



  • Registered Users Posts: 24,848 ✭✭✭✭ Wishbone Ash




  • Moderators, Business & Finance Moderators, Motoring & Transport Moderators, Society & Culture Moderators Posts: 63,170 Mod ✭✭✭✭ L1011


    There is just a slight problem with this proposal. We don't have NSL anymore, except when signed on some side roads where signing 80 would be ridiculous. The intent is definitely going to be cutting 120 and possibly 100 limits, not the 80 on a subset of roads. In '79 they just need to promote that the NSL sign now meant 55.

    Replacing lots, and lots, and lots of plastic faced metal speed limit signs would have to be quantified for its resources impact.



  • Moderators, Category Moderators, Arts Moderators, Sports Moderators Posts: 45,334 CMod ✭✭✭✭ magicbastarder


    dropping from 120km/h to 100km/h on the motorway between dublin and galway means the journey would take 1h48m rather than 1h30m, so not exactly onerous; probably would save at least 20% in fuel i suspect.



  • Registered Users Posts: 13,985 ✭✭✭✭ Fr Tod Umptious


    My first car in the US was an late 80s Honda and it had 55 marked in red on the speedometer, every other number was in white.



  • Registered Users Posts: 5,254 ✭✭✭ SouthWesterly


    Too right. I'm tired of going at 20kmh behind a tractor. I can go at 15kmh no problem 😁



  • Moderators, Category Moderators, Arts Moderators, Sports Moderators Posts: 45,334 CMod ✭✭✭✭ magicbastarder


    Replacing lots, and lots, and lots of plastic faced metal speed limit signs would have to be quantified for its resources impact.

    i'd say if the drop was successfully implented, the resource impact would be 'paid for' within less than a day. that's an absolute finger in the air guess though!



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  • Registered Users Posts: 270 ✭✭ JayPS 2288


    Don’t forget that the kinetic energy of the car is E=1/2 mv^2.

    The energy consumption increases by the square of the velocity of the car. The kinetic energy is 70% if driving at 100 km/h rather than 120.

    That’s some fuel saving for little extra time.

    And the calculation from @magicbastarder seems to be based on the assumption of driving flat out at 120 km/h from point to point. Much of that journey will involve slowing for tolls, stop start in towns. Reducing by a modest 20 km/h will have little impact.



  • Registered Users Posts: 270 ✭✭ JayPS 2288


    Taking the extreme example of driving from Malin Head to Mizen Head (even if the whole stretch was 120 km/h, which it isn’t), you’d still only “waste an hour”.



  • Moderators, Category Moderators, Arts Moderators, Sports Moderators Posts: 45,334 CMod ✭✭✭✭ magicbastarder


    Don’t forget that the kinetic energy of the car is E=1/2 mv^2.

    The energy consumption increases by the square of the velocity of the car. The kinetic energy is 70% if driving at 100 km/h rather than 120.

    you're right, but for the wrong reasons; burning fuel to increase kinetic energy only really matters during acceleration, but when at a steady speed, i.e. when kinetic energy is not changing, it doesn't take fuel to maintain KE, it takes fuel to push the air out of the way. the vast majority of fuel burn at 120km/h is overcoming air resistance, and air resistance squares with velocity.

    IIRC the bugatti veyron, which develops ~1000BHP needs 150BHP (could be 250BHP?) to get to 150mph, but another 850BHP to get to 250MPH, and that's down to the air.



  • Moderators, Category Moderators, Arts Moderators, Sports Moderators Posts: 45,334 CMod ✭✭✭✭ magicbastarder


    yeah, and soon after that you'll only be allowed go from dublin to galway if there's a good strong easterly.



  • Registered Users Posts: 11,929 ✭✭✭✭ elperello


    This link suggests that there may be more than meets the eye when it comes to marine vs. motor car emissions.

    http://www.oldsaltblog.com/2021/04/no-sixteen-large-ships-do-no-pollute-more-than-all-the-cars-in-the-world/

    Whatever about ships we actually have to pay to fill up our cars at the pump and slowing down can save us money.



  • Moderators, Category Moderators, Arts Moderators, Sports Moderators Posts: 45,334 CMod ✭✭✭✭ magicbastarder


    The sixteen largest ships emit the same amount of CO2 as all the world's cars.

    not only is that wrong, you're even getting the incorrect claim wrong.

    the claim you're parroting was about sulphur dioxide, not CO2. and even with that, the claim about SO2 doesn't stand up.

    anyway, the world's cars are estimated to produce two to four times as much CO2 as the entire global maritime fleet.




  • Moderators, Category Moderators, Arts Moderators, Sports Moderators Posts: 45,334 CMod ✭✭✭✭ magicbastarder


    huh, i should have refreshed, elperello got there before me.

    also - the claim, originally made in 2009, and based on faulty assumptions, obviously couldn't take into account that sulphur limits were dropped from 3.5% to 0.5% in 2020.



  • Registered Users Posts: 3,725 ✭✭✭ Dakota Dan


    Curtesy of the BBC f course you won’t find any independent source because it doesn’t fit the narrative.



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  • Moderators, Category Moderators, Arts Moderators, Sports Moderators Posts: 45,334 CMod ✭✭✭✭ magicbastarder


    This is not the conspiracy theories forum? The chap who originally formulated the claim was interviewed for that, how much closer to the source do you want?



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