The Wrong Way to Set Speed Limits [ST06]
The Wrong Way to Set Speed Limits [ST06] on HackerTube: recommended by 9 Hacker News commenters across 9 separate months, 2021–2025.
Not Just Bikes explains how North American speed limits are set and why posted limits matter far less than street design. It argues that drivers follow the road's cues, so safe speeds have to be built into the street.
What HN commenters said
13 Hacker News comments link this video. Each one links back to its thread.
gregmacMay 2024Strongly recommends
Europe has a lot more roads with a lower design speed. Curves, narrow lanes, on-street parking, trees/poles/etc close to the road. These things cause people to drive slower, because it doesn't feel safe to go fast. In North America, roads are usually built in the complete opposite way, with long straight roads and wide lanes, so the design speed is actually quite high -- even if that wasn't the intent. People go fast, because it feels safe to go that speed, but isn't, because there are pedestrians and turns. We then "fix" that shit road design by having low speed limits. This video is all I think of when this discussion comes up now: ▶ this video
in “Bollards: Why and What” · View on HN
CalRobertMay 2024Strongly recommends
Not much but it’s a start. Unfortunately the US treats every street and road like it’s a country road when it comes to speed limits, with a lot of deaths as a result. Great video on this at ▶ this video
in “California Senate Passes Bill Requiring Passive Speed Limiters” · View on HN
noirdujourJan 2023Strongly recommends
> MUTCD designs streets similarly to rural highways, and this can create conditions where people speed when they need to be driving slowly, because the design of the street doesn't reflect the speed the sign says you need to be driving. Not Just Bikes covers this shortfall in a video on speed limits[1], and it really opened my eyes on the relationship between rules and actual behavior. Essentially, speed limit signs affect driving speeds slightly, but the street design is important. Wide, open, straight roads naturally prompt drivers to drive to highway speeds, even in more suburb areas. It's amazing how often I check the speedometer and find that I'm driving much more than the posted speed limit when following the flow of traffic. [1] ▶ this video
in “America’s roads and highways have a big, fat style guide” · View on HN
gregmacMar 2022Strongly recommends
I think my first intro to this was from a Not Just Bikes video on speed limits [1], and that profoundly affected my opinion on this stuff. I now think a lot of road design is just utterly broken, and it includes speed limits, what that channel (and other related) refer to as "stroads", and intersections (roundabouts vs traffic lights). That video in particular is highly relevant to the speed camera thing. [1] ▶ this video
in “New speed camera ‘detect’ vehicles braking as they approach” · View on HN
TomK32Jan 2025Recommends
The road design is what causes bad or good driving. The road you describe should narrow before the blind curve so the drivers would (often enough unconsciously) slow down before it. For the pedestrian crossing, small islands that separate the lanes and give pedestrians a safe space will help. ▶ this video
in “Making an intersection unsafe for pedestrians to save seconds for drivers” · View on HN
CalRobertOct 2023Recommends
As much as the comments from complaining drivers are frustrating, it reveals that the problem here is relying on speed limits and not street design. If you want drivers to go 20mph, you need to design the street so going any faster feels uncomfortable. ▶ this video discuses this. Also, I notice that most of those drivers complaining don't address what it's like to have a small child who's a runner and is always trying to get loose of your grip and run in to the street.
in “Wales' 20mph speed limit: How has the first month gone?” · View on HN
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gcanyonNov 2022Recommends
Not Just Bikes on YouTube covers road/pedestrian/bike safety extensively. [link] Specific videos: Crossing the street should be safer: [link] How to quickly build a cycling city: [link] Wasting money on car infrastructure: [link] The wrong way to set speed limits: ▶ this video Safe cycling: [link] "Stroads" are dangerous: [link]
in “The Exceptionally American Problem of Rising Roadway Deaths” · View on HN
YawningAngelOct 2022Recommends
That's not really how speed limits work though. People take their cues from road design and conditions, not what the speed limit actually is. Virtually changing speed limits is dangerous because it causes you to think you are altering the behaviour of traffic without actually doing so. ▶ this video goes into detail on this
in “Even after $100B, self-driving cars are going nowhere” · View on HN
occzSep 2022Recommends
People don't follow speed limits, regardless of how literate they are. Relevant Not Just Bikes-video on the subject: ▶ this video
in “Heavier cars are safer for their drivers, but far deadlier for everyone else” · View on HN
ben-schaafSep 2022Recommends
Not Just Bikes has a great video covering this: ▶ this video TLDW: People don't obsessively check their speedometer and thus changing the speed limit largely doesn't affect the speed people drive at. To effectively change that you need to change the road design.
in “Heavier cars are safer for their drivers, but far deadlier for everyone else” · View on HN
xputerOct 2021Recommends
Sorry but this is just so wrong. American road design is super predicated on personal responsibility. We design roads that are as wide as freeways and then put a little sign on the side that says 35mph speed limit. What we need is less focus on personal responsibility and accept that people make mistakes, we're all human after all. Our roads should be designed with human error in mind. The road design itself should make it natural for drivers to slow down near dangerous areas. See this video for example: ▶ this video
in “Car accidents cause death, injury and trauma. Why do we shrug them off?” · View on HN
xputerOct 2021Recommends
It's not about making the roads more narrow or winding per se. It's about deliberately slowing cars down where they need to, through the road design. See this video for example: ▶ this video Besides that, roads in the US are generally poorly classified. They're often trying to both function as both high throughput roads and destination serving streets. Such hybrid roads are known as "stroads" and they're bad for everyone involved. Stroads are bad for moving cars fast due to the many conflict points (driveways, intersections, etc.) that force drivers to constantly slow down. They are also bad at serving destinations because the many conflict points make stroads very dangerous, especially if you're not in a car. See this video for example: [link]
in “Car accidents cause death, injury and trauma. Why do we shrug them off?” · View on HN
xracyNov 2022Cites it
▶ this video This feels like doubling down on something that's not super effective. The way to make traffic slower, is to make road lanes narrower. You can also add curves/trees or overhangs to add shadows to the road, which breaks up the roadway and makes it harder to reason about from a distance.
in “Speed traps have no long-term effect on speeding: study” · View on HN