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Speed and convenience also matters. I like big, fast, and wide roads because they let me and many others get to where we want to go quickly. It’s a trade off. W

Speed and convenience also matters. I like big, fast, and wide roads because they let me and many others get to where we want to go quickly. It’s a trade off. We shouldn’t let “think of the children” safetyism decide what the balance is, since that line of thinking is extremist and does not consider what is at stake on the other side of the argument. Efforts to eliminate every last death on streets are a waste of time since we’ll never achieve perfection and roads are very safe already. The road diets made under that unrealistic goal are simply making everyone’s lives worse by causing us to spend more time on the roads in traffic.

davidw 2y ago
Traffic deaths are quite literally one of the two leading causes of death of children in the United States, so in this case, yeah, actually thinking of the children makes some sense.
- m463 2y ago
  Note the way to do this is to follow engineering rules. Take the 85th percentile rule. If you take a neighborhood road and change it from 40mph to 25mph in an attempt to "save the children", you can easily make it more dangerous. The 85th percentile rule figures how fast people go on a road, and sets an appropriate speed limit that people naturally follow. Attempting to set a speed limit too low or too high leads to a wide speed variance, which makes the road more dangerous.
  - davidw 2y ago
    Or we could actually build slower, safer streets that are that way by design, rather than relying on signs. And where roads need to be fast and move a lot of cars, separate them out from other uses.
    - m463 2y ago
      and set speed limit 5-10 mph below design speed for maximum safety.
      - maxerickson 2y ago
        People go the speed they are comfortable with, not the speed on the signs. You have to design for the speed you want.
        m463 2y ago
        correct.
  - durkie 2y ago
    How does setting a speed limit "too low" make a road more dangerous?
    - m463 2y ago
      Safest roads have the speed limit 5-10 mph below the road design speed. see fig 4 on speed variance: https://www.fhwa.dot.gov/publications/research/safety/17098/003.cfm https://www.fhwa.dot.gov/publications/research/safety/17098/... going faster or slower than average traffic speed shows markedly greater accident rate. note that this can apply not only to speed limits, but things like express lanes going different speeds than other lanes
      - durkie 2y ago
        But you're saying the speed limit (being too high or low) makes the road dangerous. Aren't the people driving their cars too fast making the road dangerous?
        Leif24 2y ago
        A great many people when they see a open straight road with little obstacles or pedestrians will go 45-50 MPH. A great many people when they see a 15 MPH sign will go 20 MPH. Pair that low speed limit with a "fast" road and you will end with many people going 45 MPH and many people going 20 MPH. This variance in speed, with some people going much slower than others can be more dangerous than if most went the same speed - e.g. if the limit were 45 MPH. You are correct that people driving too fast make the road dangerous, but so does people driving too slow. Generally, from a safety point of view, you want the slowest speed at which almost everyone will actually drive at, as large variance in speed between drivers is dangerous. I think this is what the parent post was getting at: a speed limit too fast OR too slow will increase the number of accidents, keeping in mind that there will always be at least some drivers speeding.
        david-gpu 2y ago
        > You are correct that people driving too fast make the road dangerous, but so does people driving too slow. It's accurate to say that people driving too fast are extra dangerous when there are slower vehicles in the road. The danger is still caused by the people driving too fast, not by those driving slowly, though. Speed kills.
  - bryanlarsen 2y ago
    In my personal experience, automated speed cameras are way more effective than traffic calming.
    - dghlsakjg 2y ago
      I live in BC, where speed cameras are banned by law. Right next door is Alberta. Last time I was in Edmonton, known for extremely car centric design, wide roads, ample highways, etc. I was shocked by how much slower people drove, and as a result, how much safer driving was in general. You only have to get slapped with a fine a few times before you start learning to control your speed.
    - owlbite 2y ago
      I'd go further and say automated average speed cameras are the most effective I've seen. Point speed cameras just get marked on a map and cause sudden braking and acceleration to dodge them - this can be effective at particular danger spots, but I always feel the average speed cameras in the UK are far more effective at changing driver habits in general.
    - oblio 2y ago
      Yeah, but those probably cost more and don't make for a nice environment outside of cars. Traffic calming can be super cheap and it makes for a super pleasant environment for everyone.
      - bryanlarsen 2y ago
        Traffic calming is usually more expensive than speed cameras. A speed bump isn't expensive but people are usually talking about stuff like bump outs and raised intersections and protected bicycle lanes and wide sidewalks when they are talking about traffic calming. Those are six figures per intersection. Cameras are low five figures.
        oblio 2y ago
        Traffic calming can be literally some poles or some pots with plants in them. It's the cheapest form of "infrastructure" after paint.
  - bluecalm 2y ago
    The problem is that people are naturally very bad drivers and are especially bad at judging what safe speed is. We already know it's hopeless to teach them so what is left are traffic calming measures, heavy handed enforcement and technology (automatic speed limiters in cars). Setting speed limits to speed people choose is a terrible idea.
    - josephcsible 2y ago
      > Setting speed limits to speed people choose is a terrible idea. The point of the Solomon curve is specifically that that isn't true.
      - bluecalm 2y ago
        People naturally choose speeds according to how safe they feel not how safe it is for everyone else. If you have a residential area road which is straight and wide enough to go fast people will choose higher speed than on a narrow road. This proves it doesn't work unless you only care about safety of people in cars (which Salomon curve seems to based on meaning it's meaningless for road design with the exception of highways).
  - occz 2y ago
    I don't think I've ever heard someone argue that the 85th percentile rule is actually a good invention - it's a disaster that codifies the behaviour of speeding drivers. I agree that merely lowering speeds without changing the design speed is a bad move, though.
- blackeyeblitzar 2y ago
  To me that sounds like a safetyist argument. Even if the number of deaths are high in total count, it may not matter when you consider the trade offs. For example if everyone spends an hour more in traffic each day - which is what the effect of “calming” has been in my experience - you’re causing an impact that is worse than the small number of deaths in my city. That delay and damage to our life quality matters, and needs to be weighed against the rare deaths. Cars are very safe today and are getting much safer. Even basic cars come with many features to avoid accidents now. We will probably see deaths per mile driven go down on its own, without the need for malicious road design.
  - naniwaduni 2y ago
    Slowing down insidiously shaves away at your lifespan too, it just doesn't produce exciting catastrophic life loss events.
    - david-gpu 2y ago
      By that same logic, distance insidiously shaves away at your lifespan and we should build mixed-use walkable neighborhoods so that we can quickly reach our everyday destinations rather than causing traffic every time we want to get anywhere.
      - naniwaduni 2y ago
        It does! We should all live in NYC!
  - ryukafalz 2y ago
    > Cars are very safe today and are getting much safer. For their occupants, sure. For those outside cars (and remember, children can't drive) not so much: https://www.nbcnews.com/news/us-news/americas-cars-trucks-are-getting-bigger-are-front-blind-zones-children-rcna52109 https://www.nbcnews.com/news/us-news/americas-cars-trucks-ar...
    - 2y ago
alexpetralia 2y ago
Don't just think about the deaths. Think about all the injuries too. All the environmental damage. All the people that don't hang on the street because of the fumes and noise and danger. All the road rage and cortisol that boils within otherwise sane people the moment you put them behind a wheel and into some traffic. All the sedentarism and obesity from people opting to drive 2 minutes rather than walk 10. All the forgone housing for parking stadiums. I am all for convenience, but the costs are noticeable in more ways than one.
- WarOnPrivacy 2y ago
  I don't disagree but I would add this adjacent perspective. It's a bit like we've installed public-funded, unremovable alcohol spigots in everyone's home. People using them within their designed limits lead to awful outcomes. We're reasonably upset about that and respond with thousands of marginally and unequally enforced restrictions. Unhappy with their ineffectiveness, we just keep piling on more punitive restrictions. Giving up booze infrastructure isn't on the table tho. We're too dependent on it.
- AnthonyMouse 2y ago
  > All the environmental damage. Environmental damage is the argument against traffic calming measures. Vehicles are most efficient traveling at a consistent, relatively high speed. The reason the national speed limit was historically set at 55MPH was that was the approximate speed at which aerodynamic losses overcome mechanical losses from low gearing at low speeds, i.e. it was the speed that vehicles of the time were most fuel efficient. Modern vehicles have even better aerodynamics. Moreover, fuel efficiency for electric vehicles is essentially moot, because they have built-in storage that can be charged from intermittent renewable sources during times of oversupply when the power is "free". Conversely, traffic calming generally results in vehicle speed changes as motorists slow down and then speed back up again in response to obstructions or areas with intentionally low visibility, which not only wastes fuel by operating vehicles below their optimal speed, it results in braking and acceleration that increases brake dust and tire wear. Environmentally, the optimal road is flat and straight with no traffic control devices or other reasons for vehicles to change speed, i.e. a highway.
vsuperpower2021 2y ago
There's a non-trivial chance that the only reason you're around to complain about child safety is that we spent so long eliminating unnecessary dangers. The issue is speeding, not that you want to get somewhere faster than the speed limit.
Tiktaalik 2y ago
I for one think it's good to not kill children.
nox101 2y ago
Where are these mythical big, fast, wide roads? Every road I know, no matter how wide, is slow. And making it wider doesn't help because of induced demand.
- ciceryadam 2y ago
  For example check Eisenhower drive in La Quinta, California: https://maps.app.goo.gl/YdaSTfX9YwrXmU1MA https://maps.app.goo.gl/YdaSTfX9YwrXmU1MA
- jaredhallen 2y ago
  I'm not sure I buy the concept of induced demand. If you widen a road and it results in more traffic, that sounds like there was already more demand than supply.
  - lostdog 2y ago
    Induced demand should really be called "insurmountable demand." If there's a million more people who would take a traffic-clogged freeway if it were moving at 6mph, then it will always be clogged with traffic.
  - oblio 2y ago
    Have you read anything or watched anything about induced demand or did you just read the expression and figured it all out by yourself? https://www.youtube.com/watch?v=za56H2BGamQ https://www.youtube.com/watch?v=za56H2BGamQ
ndsipa_pomu 2y ago
"Fast" and wide roads don't actually help much with moving traffic around as there's such a phenomenon as induced demand. When more lanes are added to a road, more people are encouraged to drive and then the fast and wide roads get congested, especially where they join with smaller roads. There's also the geometry problem. As more roads are built and more people travel by car, the various amenities get spread further apart (e.g. more parking required) which then makes them more difficult for people to walk/cycle to. This then gets more people to make a car journey when they previously might have walked which increases the amount of traffic. As more traffic builds up, more and wider roads are built which pushes everything further apart. This then encourages more and longer car journeys which results in more congestion - the solution to which would appear to be adding just one more lane to the roads. The trick to solving congestion issues is to encourage as many people as possible to make short, non-car based journeys. Unfortunately, prioritising car journeys is almost always at the expense of other traffic.
lukas099 2y ago
There can be big, fast roads between places of interest but we build them right through our towns

davidw 2y ago

Traffic deaths are quite literally one of the two leading causes of death of children in the United States, so in this case, yeah, actually thinking of the children makes some sense.

m463 2y ago
Note the way to do this is to follow engineering rules. Take the 85th percentile rule. If you take a neighborhood road and change it from 40mph to 25mph in an attempt to "save the children", you can easily make it more dangerous. The 85th percentile rule figures how fast people go on a road, and sets an appropriate speed limit that people naturally follow. Attempting to set a speed limit too low or too high leads to a wide speed variance, which makes the road more dangerous.
- davidw 2y ago
  Or we could actually build slower, safer streets that are that way by design, rather than relying on signs. And where roads need to be fast and move a lot of cars, separate them out from other uses.
  - m463 2y ago
    and set speed limit 5-10 mph below design speed for maximum safety.
    - maxerickson 2y ago
      People go the speed they are comfortable with, not the speed on the signs. You have to design for the speed you want.
      - m463 2y ago
        correct.
- durkie 2y ago
  How does setting a speed limit "too low" make a road more dangerous?
  - m463 2y ago
    Safest roads have the speed limit 5-10 mph below the road design speed. see fig 4 on speed variance: https://www.fhwa.dot.gov/publications/research/safety/17098/003.cfm https://www.fhwa.dot.gov/publications/research/safety/17098/... going faster or slower than average traffic speed shows markedly greater accident rate. note that this can apply not only to speed limits, but things like express lanes going different speeds than other lanes
    - durkie 2y ago
      But you're saying the speed limit (being too high or low) makes the road dangerous. Aren't the people driving their cars too fast making the road dangerous?
      - Leif24 2y ago
        A great many people when they see a open straight road with little obstacles or pedestrians will go 45-50 MPH. A great many people when they see a 15 MPH sign will go 20 MPH. Pair that low speed limit with a "fast" road and you will end with many people going 45 MPH and many people going 20 MPH. This variance in speed, with some people going much slower than others can be more dangerous than if most went the same speed - e.g. if the limit were 45 MPH. You are correct that people driving too fast make the road dangerous, but so does people driving too slow. Generally, from a safety point of view, you want the slowest speed at which almost everyone will actually drive at, as large variance in speed between drivers is dangerous. I think this is what the parent post was getting at: a speed limit too fast OR too slow will increase the number of accidents, keeping in mind that there will always be at least some drivers speeding.
        david-gpu 2y ago
        > You are correct that people driving too fast make the road dangerous, but so does people driving too slow. It's accurate to say that people driving too fast are extra dangerous when there are slower vehicles in the road. The danger is still caused by the people driving too fast, not by those driving slowly, though. Speed kills.
- bryanlarsen 2y ago
  In my personal experience, automated speed cameras are way more effective than traffic calming.
  - dghlsakjg 2y ago
    I live in BC, where speed cameras are banned by law. Right next door is Alberta. Last time I was in Edmonton, known for extremely car centric design, wide roads, ample highways, etc. I was shocked by how much slower people drove, and as a result, how much safer driving was in general. You only have to get slapped with a fine a few times before you start learning to control your speed.
  - owlbite 2y ago
    I'd go further and say automated average speed cameras are the most effective I've seen. Point speed cameras just get marked on a map and cause sudden braking and acceleration to dodge them - this can be effective at particular danger spots, but I always feel the average speed cameras in the UK are far more effective at changing driver habits in general.
  - oblio 2y ago
    Yeah, but those probably cost more and don't make for a nice environment outside of cars. Traffic calming can be super cheap and it makes for a super pleasant environment for everyone.
    - bryanlarsen 2y ago
      Traffic calming is usually more expensive than speed cameras. A speed bump isn't expensive but people are usually talking about stuff like bump outs and raised intersections and protected bicycle lanes and wide sidewalks when they are talking about traffic calming. Those are six figures per intersection. Cameras are low five figures.
      - oblio 2y ago
        Traffic calming can be literally some poles or some pots with plants in them. It's the cheapest form of "infrastructure" after paint.
- bluecalm 2y ago
  The problem is that people are naturally very bad drivers and are especially bad at judging what safe speed is. We already know it's hopeless to teach them so what is left are traffic calming measures, heavy handed enforcement and technology (automatic speed limiters in cars). Setting speed limits to speed people choose is a terrible idea.
  - josephcsible 2y ago
    > Setting speed limits to speed people choose is a terrible idea. The point of the Solomon curve is specifically that that isn't true.
    - bluecalm 2y ago
      People naturally choose speeds according to how safe they feel not how safe it is for everyone else. If you have a residential area road which is straight and wide enough to go fast people will choose higher speed than on a narrow road. This proves it doesn't work unless you only care about safety of people in cars (which Salomon curve seems to based on meaning it's meaningless for road design with the exception of highways).
- occz 2y ago
  I don't think I've ever heard someone argue that the 85th percentile rule is actually a good invention - it's a disaster that codifies the behaviour of speeding drivers. I agree that merely lowering speeds without changing the design speed is a bad move, though.
blackeyeblitzar 2y ago
To me that sounds like a safetyist argument. Even if the number of deaths are high in total count, it may not matter when you consider the trade offs. For example if everyone spends an hour more in traffic each day - which is what the effect of “calming” has been in my experience - you’re causing an impact that is worse than the small number of deaths in my city. That delay and damage to our life quality matters, and needs to be weighed against the rare deaths. Cars are very safe today and are getting much safer. Even basic cars come with many features to avoid accidents now. We will probably see deaths per mile driven go down on its own, without the need for malicious road design.
- naniwaduni 2y ago
  Slowing down insidiously shaves away at your lifespan too, it just doesn't produce exciting catastrophic life loss events.
  - david-gpu 2y ago
    By that same logic, distance insidiously shaves away at your lifespan and we should build mixed-use walkable neighborhoods so that we can quickly reach our everyday destinations rather than causing traffic every time we want to get anywhere.
    - naniwaduni 2y ago
      It does! We should all live in NYC!
- ryukafalz 2y ago
  > Cars are very safe today and are getting much safer. For their occupants, sure. For those outside cars (and remember, children can't drive) not so much: https://www.nbcnews.com/news/us-news/americas-cars-trucks-are-getting-bigger-are-front-blind-zones-children-rcna52109 https://www.nbcnews.com/news/us-news/americas-cars-trucks-ar...
  - 2y ago

alexpetralia 2y ago

Don't just think about the deaths. Think about all the injuries too. All the environmental damage. All the people that don't hang on the street because of the fumes and noise and danger. All the road rage and cortisol that boils within otherwise sane people the moment you put them behind a wheel and into some traffic. All the sedentarism and obesity from people opting to drive 2 minutes rather than walk 10. All the forgone housing for parking stadiums. I am all for convenience, but the costs are noticeable in more ways than one.

WarOnPrivacy 2y ago
I don't disagree but I would add this adjacent perspective. It's a bit like we've installed public-funded, unremovable alcohol spigots in everyone's home. People using them within their designed limits lead to awful outcomes. We're reasonably upset about that and respond with thousands of marginally and unequally enforced restrictions. Unhappy with their ineffectiveness, we just keep piling on more punitive restrictions. Giving up booze infrastructure isn't on the table tho. We're too dependent on it.
AnthonyMouse 2y ago
> All the environmental damage. Environmental damage is the argument against traffic calming measures. Vehicles are most efficient traveling at a consistent, relatively high speed. The reason the national speed limit was historically set at 55MPH was that was the approximate speed at which aerodynamic losses overcome mechanical losses from low gearing at low speeds, i.e. it was the speed that vehicles of the time were most fuel efficient. Modern vehicles have even better aerodynamics. Moreover, fuel efficiency for electric vehicles is essentially moot, because they have built-in storage that can be charged from intermittent renewable sources during times of oversupply when the power is "free". Conversely, traffic calming generally results in vehicle speed changes as motorists slow down and then speed back up again in response to obstructions or areas with intentionally low visibility, which not only wastes fuel by operating vehicles below their optimal speed, it results in braking and acceleration that increases brake dust and tire wear. Environmentally, the optimal road is flat and straight with no traffic control devices or other reasons for vehicles to change speed, i.e. a highway.

vsuperpower2021 2y ago

There's a non-trivial chance that the only reason you're around to complain about child safety is that we spent so long eliminating unnecessary dangers. The issue is speeding, not that you want to get somewhere faster than the speed limit.

Tiktaalik 2y ago

I for one think it's good to not kill children.

nox101 2y ago

Where are these mythical big, fast, wide roads? Every road I know, no matter how wide, is slow. And making it wider doesn't help because of induced demand.

ciceryadam 2y ago
For example check Eisenhower drive in La Quinta, California: https://maps.app.goo.gl/YdaSTfX9YwrXmU1MA https://maps.app.goo.gl/YdaSTfX9YwrXmU1MA
jaredhallen 2y ago
I'm not sure I buy the concept of induced demand. If you widen a road and it results in more traffic, that sounds like there was already more demand than supply.
- lostdog 2y ago
  Induced demand should really be called "insurmountable demand." If there's a million more people who would take a traffic-clogged freeway if it were moving at 6mph, then it will always be clogged with traffic.
- oblio 2y ago
  Have you read anything or watched anything about induced demand or did you just read the expression and figured it all out by yourself? https://www.youtube.com/watch?v=za56H2BGamQ https://www.youtube.com/watch?v=za56H2BGamQ

ndsipa_pomu 2y ago

"Fast" and wide roads don't actually help much with moving traffic around as there's such a phenomenon as induced demand. When more lanes are added to a road, more people are encouraged to drive and then the fast and wide roads get congested, especially where they join with smaller roads. There's also the geometry problem. As more roads are built and more people travel by car, the various amenities get spread further apart (e.g. more parking required) which then makes them more difficult for people to walk/cycle to. This then gets more people to make a car journey when they previously might have walked which increases the amount of traffic. As more traffic builds up, more and wider roads are built which pushes everything further apart. This then encourages more and longer car journeys which results in more congestion - the solution to which would appear to be adding just one more lane to the roads. The trick to solving congestion issues is to encourage as many people as possible to make short, non-car based journeys. Unfortunately, prioritising car journeys is almost always at the expense of other traffic.

lukas099 2y ago

There can be big, fast roads between places of interest but we build them right through our towns