The Welsh parliament has passed a law bringing down the speed limit on all residential roads and busy streets to 20 mph (30 km/h). Not everyone is pleased.
  • @[email protected]
    -11•1 year ago

    Wouldn’t this, in the end, make cars have to shift to a lower gear, thus keeping about the same RPM, and thus eating about the same amount of fuel, which results in about the same volume of the sound produced by the car?

    This feels like a terrible fix.

    • A Zeppelin
      16•1 year ago

      afaik most of the sound comes from the tires, not necessarily the engine or the exhaust. obviously not the case for every car, but for most commuter cars it is. the faster the tires are rolling, the louder the sound.

      • oo1
        5•1 year ago

        i think at higher speeds the wheel and road noise drowns out the engine noise, but at lower speeds its the engine, especially during acceletation.
        in the region of 20-30mph i’d think the engine is probably the louder part.

    • the post of tom joad
      13•1 year ago

      While this is a point the naysayers brought up, the slower speeds during the trial period reduced accidents, the severity of accidents, and the slower speeds encouraged more foot and bicycle traffic on those roads

      • TipponEnglish
        2•1 year ago

        Do you know when the trial period was?

        I ask because the Welsh government apparently carried out a pollution test to justify the lowered speed limit on the main road into the capital, but did it during the Covid lockdown, when most cars were off the road.

    • @[email protected]
      7•1 year ago

      Wouldn’t this, in the end, make cars have to shift to a lower gear, thus keeping about the same RPM, and thus eating about the same amount of fuel

      That’s not how cars work, they definitely don’t use the same fuel in different gears at the same RPM. See this Wikipedia article for a discussion of speed vs fuel economy.

      And as pointed out by the the FAQ, that’s doesn’t not factor in acceleration:

      Will driving at 20mph mean I use more fuel?

      No. Fuel consumption is mainly influenced by the way we drive – driving at a consistent speed is better than stopping and starting. Accelerating up to 30mph can take twice as much energy as speeding up to 20mph.

      A default 20 mph limit and a smooth driving style, can help avoid unnecessary speeding up and slowing down, saving fuel.

    • @[email protected]
      7•1 year ago

      Most cars, at least in NA, have excessively large engines. It is crazy that we use 2L engines to carry one person around, when their own legs would suffice.

    • @[email protected]
      4•1 year ago

      A lot of cars can cruise at 20-25mph just idling in Drive, foot completely off both gas and brake. The RPMs don’t get much lower than that.

    • oo1
      3•1 year ago

      if the cars are designed to use the same fuel for less useful output power, then they’re very badly designed.
      i’m sure they might be less efficient in terms of miles per gallon. but they surely can’t be so bad as to waste absolutely more fuel at lower speeds.

      if they are, fuck them.