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Comment by Gigachad | Hacker News Reader

There are still ways to improve safety, mostly by just slowing traffic down. These cars kill at any speed, but they are significantly less likely to if traveling at say 30km/h.

Narrow lanes, reduce visibility, add complexity and turns. Traffic will naturally slow down with drivers paying more attention. It's been demonstrated that the easier you make a road to drive on, the more people speed and play with their phones.

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Thanks, those are all generally good ideas. I realized another would be to provide separate paths for pedestrians and vehicles (beyond just sidewalks), but that may be difficult to implement in many suburban neighborhoods.

>These cars kill at any speed, but they are significantly less likely to if traveling at say 30km/h.

There is literally no way in hell that you are going to get anyone in the US with a large truck or SUV to drive under 20mph

You can, switch the roads to brick/stone, and make it narrow enough that unless you crawl relatively slowly, you are at risk of scraping on things on the sides.

something tells me you are not very familiar with sheer number and miles of roads there are in the US.

I imagine only streets with pedestrian traffic would have to be changed, not inter-city roads and highways.

If you're in the Bay Area, I invite you to drive around on Middlefield Rd in the 25mph sections to see how well setting speed limits way below what most drivers would consider reasonable works in practice (most people travel ~35-45mph there).

Further reading if you're really curious about this situation in particular, there's been a lot of back and forth around Menlo Park / Atherton specifically: - https://www.ci.atherton.ca.us/DocumentCenter/View/8751/Engin... - https://www.almanacnews.com/news/2020/10/22/menlo-park-counc... - https://www.paloaltoonline.com/news/2016/11/17/palo-alto-eye... - https://www.cityofpaloalto.org/files/assets/public/agendas-m... - on 85th percentile theory: https://dot.ca.gov/programs/safety-programs/setting-speed-li...

Particularly amusing is https://www.mercurynews.com/2016/11/30/radar-isnt-best-optio... ... where most people seem to agree that everyone drives too fast, but in order to use radar / lidar to measure speed, they'd need to comply with state law which would mean /raising/ the speed limits in order to comply with the 85th percentile rules, so instead they just stick their heads in the sand and continue to believe, despite many studies finding to the contrary, that zero enforcement and a sign that says 25mph will actually get people to drive on 5-lane roads at ridiculously slow speeds. This leads to an exciting mix of a few cars trying to actually drive the 25mph speed limit while most other people try to frantically pass them. Extra fun on sections that don't have left turn lanes, where the left of the two lanes becomes the de-facto turn lane, then combine that with the general lack of turn signal usage and you get...a very frustrating commute indeed. But what do you want for your $3m 1000sqft single-family home in those neighborhoods??

Edit: there's a lot more traffic engineering theory around speed limits vs how fast people actually drive. The last couple of points in particular are extra fun: https://www.saratoga.ca.us/DocumentCenter/View/998/Setting-S...

    The rationale for speed zoning is also based on the following fundamental concepts, which are
    deeply rooted in our system of government and law:
    •  The normally careful and competent actions of a responsible person should be considered legal.
    •  Laws are established for the protection of the public and the regulation of unreasonable
    behavior by the individual.
    •  Laws cannot be effectively enforced unless the majority of people voluntarily consent to and   
    comply with them.
 
    In general, most people accept, understand, and follow these concepts. But, as mentioned
    earlier, when confronted by local traffic challenges—an increase in traffic volumes or the frequency
    or severity of car crashes in a particular area, for example—people often reject these concepts and
    rely instead on a number of widely held misconceptions, such as:
    •  Lowering a posted speed limit will reduce traffic speeds.
    •  Raising a posted speed limit will increase traffic speeds.
    •  Lower speed limits will reduce the rate of crashes and increase safety.
    •  Any posted speed limit is safer than an unposted speed limit.
 
    In fact, these commonsense notions are not supported by studies, which consistently
    demonstrate that:
    •  The speed of traffic does not change significantly after new or revised speed limits are posted.
    •  There is no direct relationship between posted speed limits and the frequency of traffic
    crashes.

Lane width vs speed is interesting to read about too: https://nacto.org/docs/usdg/review_lane_width_and_speed_pars... (tl;dr people will naturally drive more slowly on streets with street parking, narrow lanes, curves, driveways, visible foot traffic, etc, and drive more quickly when roads are visibly more open)

I haven't seen an American road like that on previous discussions about urban planning in the USA. It's interesting to compare with an urban road in Europe. It's been painted very similarly -- narrowed lanes, regular "25" numbers on the road, the unwanted lanes turned into car parking. You can find that all over Europe in places where there's not much budget but speeds need to be reduced.

But the main difference is the length, and the straightness.

I'm afraid I don't have any solutions.

Possibly it's still a bit wide -- the middle could be painted as a 0.5m wide hatching rather than just a single/double line, or maybe bike lanes could be fitted between parked cars and the existing kerb, but that is probably tight.

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