• stankmut@lemmy.world
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      1 year ago

      It does increase the capacity of roads. Two lanes holds twice as many cars as one lane. Four lanes hold twice as many cars as two lanes.

      You're probably thinking of induced demand, but that's related to traffic congestion and not capacity. More lanes ultimately means more cars are getting places, but any individual car will see that congestion is just as bad as it used to be.

      • Swedneck@discuss.tchncs.de
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        1 year ago

        yeah see what's happening here is that you're completely ignoring junctions: even in the ideal case of a completely straight road you still need junctions to get on and off the road, which will put a hard limit on throughput.

        This is why traffic in america is miserable, the traffic engineers fail to recognize that you can't just put businesses right next to roads as that will cause stupendous amounts of choking every time someone wants to pop in for some mcdonalds.

        3 lanes in each direction is about the most you'll ever need, which is what you'll tend to see on big highways in europe. And really most of the time you'll do just fine with 2 lanes.

        • stankmut@lemmy.world
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          1 year ago

          I actually had a whole paragraph about junctions being a limit and then deleted it since i didn't feel like it added to my point. I also was going to add a point about how much space the lanes take up and that even if more lanes added capacity, it didn't necessarily mean they were the right option.

        • SwampYankee@mander.xyz
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          1 year ago

          This is why traffic in america is miserable, the traffic engineers fail to recognize that you can’t just put businesses right next to roads as that will cause stupendous amounts of choking every time someone wants to pop in for some mcdonalds.

          Yeah, fuckin' Americans, putting their McDonald's right next to roads… I mean, just look at this. What a disgrace.

          • Swedneck@discuss.tchncs.de
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            1 year ago

            yeah uh, you do realize stockholm is infamous for having shit traffic, right? Precisely because it took a lot of the road design from the US.

            Your example only proves my point.

            • SwampYankee@mander.xyz
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              1 year ago

              I'm just struggling to imagine where you would put a business except for next to a road, regardless of whether there are cars on that road or not.

              • Swedneck@discuss.tchncs.de
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                1 year ago

                there's a difference between a road and a street, a road is meant for quick throughfare and streets are destinations.

                what happens a lot especially in america is trying to do both at once, which results in a street that is incredibly stressful to try and enter/leave and is miserable to be near outside of a car, and yet doesn't allow traffic to flow smoothly and quickly.

                These are commonly referred to as "stroads", and the solution is to decide whether you want a street or a road and design it as such. In dense areas this means you have to bite the sour apple and accept that not everything can be a dedicated throughfare, the best solution is a backbone network of throughfares with streets branching off.
                In less dense areas you can have the best of both worlds by simply putting a street on the side of the road, with some greenery between them so people have somewhat of an enjoyable view, and then connect the streets to the road at either end.

    • pete_the_cat@lemmy.world
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      1 year ago

      Yeah… That's how these things work ya know. A 4 lane road has higher capacity than a 2 lane road assuming there arent any choke points.

      • Swedneck@discuss.tchncs.de
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        1 year ago

        yeah uh, i think you'll find that you need junctions, which create chokepoints?

        even with highways you get chokepoints at the ramps, and they are extremely absurdly costly.