mad

Karma: 332

mad 1 Jan 2024 23:30 UTC
8 points
0
on: shortcut roundabouts
From a traffic engineer’s perspective:
- Roundabouts can run into efficiency issues when the two traffic directions don’t have roughly even flow. The shortcut roundabout seems as though it is intended for intersections with a primary and secondary route, with the primary route having the through lane
- This sort of “hamburger” roundabout is similar to your proposal: https://www.bristolworld.com/news/hamburger-roundabout-plans-for-a4174-bristol-ring-road-shelved-after-overwhelmingopposition-3443196
- Note that your proposed roundabout will not be as safe as a traditional roundabout as the through traffic and circulating traffic can collide at a right angle and at a decent speed (the deflection in the middle isn’t going to be super effective at slowing vehicles, but I love that you thought to include it!). The safety benefit of a roundabout comes from reduced speeds (due to pre-deflection and circulating speed) and the reduced impact angles, both of which are affected by your proposal.
- Drivers doing a u-turn while vehicles are stopped on the circulating carriageway at a first pass makes me very uncomfortable but I’d have to think about it seriously / do research on it to work out whether it’s actually a bad idea or if I’m just afraid of anything different to the status quo. Early thoughts are it will confuse drivers (both not knowing how to perform the manouvre/that they can perform the manouvre, and also drivers who witness vehicles doing it won’t be sure what’s happening), and the efficiency benefits are probably minor
Note that my specialty is in improving safety rather than efficiency. I have experience in project work where I had to balance them, but the above is all strongly biased towards discussing safety.

mad 12 Dec 2023 0:12 UTC
3 points
0
in reply to: Said Achmiz’s comment on: Deeply Cover Car Crashes?
I think I’m making a distinction between using it colloquially (i.e. I can say that my uncle is tall, which can be true, but it doesn’t tell you much about my uncle’s actual height) and using it with the rigor that Bezzi implied (i.e. “has someone studied this clear category of cautious drivers”?)
Then again, my example here seems to have failed because people do study tallness: https://www.sciencedirect.com/science/article/abs/pii/000291499390523F , but they crucially define tallness as above the 95th percentile. Other studies I’m glanced at use height as a continuous variable, so who the heck knows.

mad 11 Dec 2023 22:51 UTC
1 point
0
in reply to: Said Achmiz’s comment on: Deeply Cover Car Crashes?
Yeah, okay.
Look at me thinking like an engineer—“but it’s not useful from a practical point of view because we don’t have access to that data”.

mad 11 Dec 2023 22:20 UTC
4 points
0
in reply to: Bezzi’s comment on: Deeply Cover Car Crashes?
I think the thing you’re missing is you’re still exposed to crashes because of some maniac doing something extremely risky and hitting you.
I’m also a very cautious driver (as you can imagine in my line of work), but I do make mistakes all the time.
This paper seems like it might be interesting for you to read: https://www.pnas.org/doi/epdf/10.1073/pnas.1513271113
I’ve just had a skim but here’s some of my impressions. I might read it in more detail when I get to work today.
It doesn’t deal with fatalities (just crashes) but having a quick look at Fig 1, drivers who aren’t distracted or impaired are involved in ~28% of crashes. Note that “impairment” also includes things like anger.
Fig 2 is pretty great for you—shows the baseline of each type of impairment, error, distraction and the odds ratio for crashes it’s involved in. Not a statistician but I believe that means you’re 10 times more likely to get into a crash if you’re visibly angry/sad but only 3 times more likely if you’re drowsy. Which is very interesting to know.
And that 51% of drivers are observed to be distracted in some way during normal driving condition (which can include “dancing in seat to music” and “interaction with adult passenger”.
This paper was just the first result in a scholar search for the term “crash causation factors driver”, so this info is relatively easy to find.
What links here?
- Said Achmiz's comment on Deeply Cover Car Crashes? by jefftk (11 Dec 2023 23:24 UTC; 3 points)

mad 11 Dec 2023 22:11 UTC
1 point
0
in reply to: Joachim Bartosik’s comment on: Deeply Cover Car Crashes?
“Passenger mile” is not a stat we use in my jurisdiction (we use VKT, vehicle kilometres travelled), but if I’m interpreting it right, then you need to know the average number of passengers to know the number of crashes the driver is involved in. For example, say that each bus has 10 passengers on average, that would put the fatalities per passenger mile at 0.80, which given this is OOM seems pretty similar to cars.
That said, following that to its conclusion you’d end up with trains having some horrendously high rate of crashing, which doesn’t pass the sniff test. I think I might be having a failure of logic somewhere here.

mad 11 Dec 2023 22:06 UTC
4 points
3
in reply to: Said Achmiz’s comment on: Deeply Cover Car Crashes?
I mean it doesn’t describe something objective/measurable unless you define it explicitly in terms of behaviours. People can do research on e.g. crash rates for drivers who never drink and drive vs frequently drink and drive, people who speed and people who don’t, etc.

mad 11 Dec 2023 13:23 UTC
3 points
0
in reply to: Bezzi’s comment on: Deeply Cover Car Crashes?
I can’t believe you’ve never heard the stereotype that taxi drivers aren’t safe drivers.
I don’t know about proxies for “careful driving”. That is not my area of expertise.
That said, it’s well-known that professional race car drivers die in car crashes at higher rates during their general driving (I don’t fancy digging up a citation; you can google it yourself).
I always think of the old chestnut that something like eighty percent of people think they’re above average at driving.
I attended a training course recently that stated that educating drivers about the dangers of texting while driving is not very useful, as everyone thinks that they are careful with how and where they choose to text (e.g. only while stopped), but they agree that other drivers shouldn’t. Apparently, they reckon it’s most effective to tell people “if you text and drive, your kids will grow up to text and drive too”. Psychology, eh?
I think all of those are very illustrative of the biases people have in how perceive their operation of their vehicles.
I am relatively convinced that 95% of crashes involve a variety of factors contributing (swiss cheese model). There is rarely, if ever, only one thing that causes a serious crash. As a road safety professional, then, my duty is to make sure that the road forgives any human errors. Safe Systems is the current philosophy in road safety, which states that nobody should be seriously injured or die on the road, even though people do make mistakes. And they do. All the time.

mad 11 Dec 2023 12:44 UTC
7 points
0
in reply to: Bezzi’s comment on: Deeply Cover Car Crashes?
https://acrs.org.au/files/arsrpe/RS050099.pdf ← there’s a paper that covers your exact question (comparing crashes in taxis and passenger cars. in case you don’t know the terminology, “fleet vehicle” refers to cars that are registered as work cars for an organisation, so more likely to be people on their “best behaviour” as far as drinking/speeding/etc)
Table 5 in particular, per 100 million vehicle kms travelled you have taxis having about half as many fatal crashes as cars but about 50% more injury crashes and maybe 10% more towaway crashes (eyeballing it)
Table 10 also shows that some 30% of taxi drivers involved in crashes weren’t wearing seat belts (they’re apparently not legally required to in NSW! news to me), which is a pretty big clue that taxi drivers aren’t the paragon of careful driving one might assume.

mad 11 Dec 2023 12:23 UTC
8 points
1
in reply to: Bezzi’s comment on: Deeply Cover Car Crashes?
“Cautious driver” is not a real category. It’s not something my crash database can filter on.
You make mistakes when you drive. We all do. It is human nature, and driving is a complex chain of tasks.
If you never speed, never drive after even one drink, never break a single road rule, know every single road rule (in my jurisdiction the road traffic code is some 400 pages long!), never take gaps in traffic that are too close, never go through an orange light too late, never jaywalk, always ensure your car is mechanically up to date, etc etc etc, then you are either pathological about your rule following or a liar.
I do crash analysis as part of my job, almost every day. I can tell you there are PLENTY of bus crashes—buses going before the passengers were sat down resulting in minor injuries, buses hitting pedestrians resulting in hospitalisation, heck I was in a bus about a year ago that rear-ended a car in front of it. I only have access to data in one jurisdiction and I don’t believe that data includes taxis, uber drivers, etc. Anecdotally my uber drivers often adjust the GPS when they’re driving and tend to speed so I wouldn’t call them particularly cautious.
For the record, as far as I know I don’t have the right to pull out my jurisdiction’s crash data so I won’t be able to respond to specific requests. I do know that “bus” is a category of vehicle we have. I don’t know whether taxi is.
EDIT:
https://www.9news.com.au/national/liverpool-crash-pedestrian-dies-hit-by-bus-sydney-south-west/6eba1c4a-0825-4828-87c1-b530e5e4e2b5 - a man in Sydney died after being hit by a bus a month ago
https://thewest.com.au/news/traffic/perth-crash-man-hit-by-bus-on-wellington-street-as-police-close-road-c-12809596 (paywall i can’t bypass) - a man in Perth was hit by a bus last week

seriously I just searched for “pedestrian hit by a bus” and there are SO MANY in Australia. With a cursory search I see three in Perth (2 million in the greater metro area) in the last six months.

mad 11 Dec 2023 2:01 UTC
40 points
2
in reply to: Bezzi’s comment on: Deeply Cover Car Crashes?
Hi! This is my area of expertise—I work in the road safety field and spent 9 months investigating fatal car crashes. You are right that there are definite “Darwin Award” candidates but there are also deeply relateable ones that could happen to anyone.
Some anecdotes off the top of my head:
- A person accidentally had their car in reverse instead of forward when manouvering after leaving a parking spot. This resulted in their car falling into the ocean and the passenger dying.
- A very common crash type that usually results in very little damage: two vehicles on a back street colliding. At this particular crash, one of the passengers died.
- An ambulence transporting a passenger (so no sirens) was hit by a vehicle driving in the wrong direction. The ambulence passenger died. (i.e. it is not always the driver at fault who dies)
- A parent was driving their child home from school, so no doubt took this route every day and was presumably not drunk/high. On this day, they ended up hitting a tree when they were going around a corner (cause: speed? wet? tyres had gone bald? loose sand on the road? the curve was too tight for the speed limit of the road? kid said/did something distracting? who knows! probably a combo!)
Data shows that changing the law on what is permitted (speeds, BAC, seat belts, etc) results in corresponding reductions in fatal crashes. Fatal crashes have halved in Australia (my jurisdiction) since around 1980, despite the population rising.
Here’s a good infographic from the WHO showing each country’s level of regulation around driving and related activities: https://extranet.who.int/roadsafety/death-on-the-roads/#ticker
The thing about human error is that you make errors ALL THE TIME. You, or other road users, should not die because of your errors. And the errors that tend to result in fatal crashes are not “I was drunk and on meth and speeding” (though those obviously do), the ones that more commonly result in fatal crashes are “I looked away from the road for a second to adjust my GPS and hit a pedestrian”.
You’ll see statistics quoted around the place about human error is involved in 94% of crashes. That is highly misleading. That doesn’t mean 94% of fatal crashes involved a sleepy drunk person at the wheel, “human error” includes stuff like misjudging the gap in traffic, not reading a sign correctly, etc. The sorts of mistakes we all make on the road all the time.
As a road safety professional, it’s my role to make sure the road is as easy to perceive as possible (e.g. ensuring adequate sight distances, signs that can be noticed and interpreted at appropriate places, sensible line markings, etc), but also to make the roads forgiving of errors when they do happen.
I think this has ended up being a kind of a rant and I apologise for that but this is a very common misconception and is very damaging to efforts to advance road safety.

mad 10 Jul 2023 22:27 UTC
23 points
7
on: I think Michael Bailey’s dismissal of my autogynephilia questions for Scott Alexander and Aella makes very little sense
As a cis woman I experience both autogynephilia and autoandrophilia and I agree this should be talked about more. For me it’s part of more generalised “power fantasies”, with the power of being attractive to men (as any gender) being exciting in the same way e.g. the idea being worshipped as a goddess is exciting.
One of my oldest and strongest fantasies is of going to a frat party and being the most beautiful woman anyone there has ever seen. I’d imagine for other people it is less about power and more about whatever their personal psychology enjoys.

mad 23 Feb 2023 22:52 UTC
20 points
9
on: Somerville Roads Getting More Dangerous?
I’m a traffic engineer and this sort of thing is more or less my area of expertise. I feel weird posting “I have nothing to add, seems legit” but I feel like if I wrote a blog post like this as a layman I’d like to know I wasn’t completely off my rocker.
My only suggestion would be if the data allows you to also get “serious injuries”—those are a bit less variable than fatalities and will be able to give you a better picture of the trend, because there’s also going to be more of them.
I used to do fatal crash investigation, and fatalities can be very random. You hear about horrific car crashes at high speeds where everyone walks away without a scratch. What you don’t hear about is the sort of crash I attended once: a tiny, slow crash on a back road at a low speed, where two cars hit each other at a small suburban intersection. Barely any damage to the cars. No sign of the crash on the road or the vicinity (fatal crashes often have damaged vegetation, marks on the road, etc). But one of the passengers was an 84 year old woman and that crash was more than her body could take. If she hadn’t been in the car, there would probably have been zero fatalities in that crash. I saw another similar crash with a man in his 80s.
That was what surprised me the most about doing fatal crash investigation: I was expecting there to be men in their 20s and 30s who were drunk or high. I wasn’t expecting the number of suicides but it didn’t surprise me. But the number of “old people” who died, I hadn’t expected that even though it’s so obvious in retrospect.
But yeah, that sort of thing is why I think “serious injuries” or “hospitalisations” might be a better metric for you: there will be 10-100x more of them so the trend will be less noisy.

mad 1 Feb 2023 22:54 UTC
3 points
0
in reply to: ChristianKl’s comment on: Iron deficiencies are very bad and you should treat them
Sorry I only just saw this post. I would not classify myself as “in the field”, for what it’s worth. I would consider “my field” to be traffic engineering, as I have 10+ years experience in that (not including undergrad). My experience in the field of nutrition is less than that (a 3 year undergrad degree).
The main part of my post is a blog post I made aimed at an intelligent lay audience, so I did leave some nuances out. I do not consider the fact that the NRVs are published by a body that doesn’t (and with current technology can’t) know the “true” RDI to be the major shortfall that you clearly think it is.

mad 20 Jan 2023 21:36 UTC
1 point
0
on: COVID contagiousness after negative tests?
I mean, you don’t? You can look it up but recent advice was something like 10 days after first symptoms is when contagiousness reduces.
Anecdotally, my husband was sick on Friday and took rapid tests on Friday and Saturday (when he was very sick) and got negative. Then on Monday his rapid test was positive (followed by a positive PCR on Tuesday). So he was no doubt contagious on two days when he gave negative tests.

mad 12 Jan 2023 11:50 UTC
34 points
0
on: Iron deficiencies are very bad and you should treat them
I have always respected your posts so when I saw your title was about iron deficiencies I was buckled in. You know that old adage, “when the newspaper reports on your area of expertise it’s crap, and yet you believe the rest of it”—I always pay special attention to what people I trust/respect say about things I know a lot about, especially when there’s a lot of misinformation out there.
I have just completed the requirements for a bachelor’s degree in Nutrition with a focus in biochemistry. I am not a dietitian and will freely admit I know less about iron than you do after this lit review. But what you said makes sense and is scientifically grounded and dovetails with the stuff I know “formally”. tl;dr I am thrilled to know that I can trust all your future posts.
I did recently write a draft blog post about iron aimed at a general audience as part of an internship, and I think a few of the things I say in there will provide useful context and background.
And yes, menstruating is definitely the reason why women are recommended more—I found the original paper where that recommendation comes from and that’s what they talk about.
One thing I have to add - ‘black stools’ are also a common side effect of iron supplementation, as well as constipation, that doesn’t mean you have iron toxicity. But taking “chelated iron” avoids that side effect.
Before I start talking about iron, I want to take a step back and talk about two concepts in nutrition that are often not well communicated to the public: the RDI and the EAR.
You’ve probably seen food labels that talk about the “% RDI” of different nutrients, and you might even know that it stands for “recommended dietary intake”. There’s another concept that goes along with it that you won’t find on nutrition labels: the EAR, or “estimated average requirement”. The RDI is the daily intake that will be enough for 97.5% of people, and is used when checking if an individual is consuming enough of a nutrient. The EAR is the intake that will be enough for 50% of people, and is used in nutrition research to check if a population is consuming enough of a nutrient.
These numbers are pretty close for most nutrients, but for iron they can be very different. The iron RDI for adult men is 8 mg/day and the EAR is 6 mg/day. Similarly, the RDI for post-menopausal women is 8 mg/day and the EAR is 5 mg/day. So the RDI and EAR are 2-3 mg apart. In comparison, for women who menstruate, the RDI is 18 mg/day and the EAR is 8 mg/day — a 10 mg difference!
To put that in concrete terms, imagine 100 women of childbearing age in a room (and none are pregnant or breastfeeding). 50 of them would be perfectly healthy consuming 8 mg or less of iron a day. 48 would need between 8 mg and 18 mg a day. And two of them would need even more than 18 mg!
So, even though the food labels recommend 18 mg of iron for women in this age range, half of them will have enough iron eating less than half the recommended amount — and 2% will need even more than the recommendation! This is why some people will have low iron levels, and other people who eat almost identical diets will have good levels. There’s a lot of variation in iron needs in this particular group and it comes down to variability in menstrual losses: for example, some women in this age group don’t menstruate at all and some may experience very heavy periods.
I’ve noticed this in the vegetarian community: a lot of people will say vegetarians don’t need to take iron supplements because their own iron levels are great, citing spinach or some other iron-rich vegetable as the reason for this. A cup of raw spinach contains 0.8 mg of iron, and the RDI is 18 mg. A typical daily “women’s multivitamin” contains around 5 mg of iron, the equivalent of 6 cups of raw spinach, every single day! For comparison, 100g of tofu contains about 3 mg of iron and 100g of beef contains about 3.5 mg of iron. It is most likely that people claiming that they don’t need iron supplements happen to be ‘lucky’ and need lower intakes.
On the subject of vegetarianism, contrary to popular belief, vegetarians and vegans tend to consume about the same amount of iron as people eating a typical western diet and are at similar risk of deficiency (https://academic.oup.com/ajcn/article/70/3/353/4714844 and https://www.mja.com.au/journal/2013/199/4/iron-and-vegetarian-diets ). However, due to the reduced absorption of iron from plant foods (18% is absorbed from a mixed western diet but only 10% from a vegetarian diet), it is recommended that vegetarians consume 80% more iron.
This is because there are two types of iron: heme iron, from animal sources, and non-heme iron, from plant sources. Heme iron is more easily absorbed, which is why vegetarians need more iron. A misconception about heme and non-heme iron is that all iron in meat is heme, but in fact, more than half of iron in meat is non-heme. So, 100g of beef would contain about 2 mg of non-heme iron and 1.5 mg of heme iron, while 100g of tofu contains 3 mg of non-heme iron. Non-heme iron absorption can be improved by consumption of vitamin C, which is abundant in most vegetarian and vegan diets.
So, where does all that leave us?
The only way to be sure of your iron status is to have a blood test, as I recommended in the previous article [unpublished; basically a much simpler version of the OP]. If your levels are low, you may want to incorporate more iron-rich foods in your diet, and ensure you consume vitamin C around the same time. You may also want to consider a supplement, especially if you have heavy periods. Whatever you do, you should get follow-up blood tests to ensure that it is working.
Iron supplements can often cause dark stools and constipation, so you may want to try several brands to find one that works for you. Some iron supplements contain “chelated iron”, which is more gentle on the stomach. [plug for advertised product removed]. For treatment of deficiencies under appropriate medical supervision, high-dose Ferrograd-C is available from pharmacies [in Australia]—though this contains non-chelated iron.
Finally, do not take high doses of iron supplements outside of medical supervision: they can be dangerous.

mad 30 Dec 2022 2:59 UTC
9 points
6
on: Effective ways to find love?
I’m a straight woman who for whatever reason seems to date a lot of men who have never had a girlfriend before (as I get older it is happening less for obvious reasons) - but these include two men who had never been kissed in their mid-30s. I tend to mostly date “rationalist” type guys.
The other advice given here is useful as general advice, but I would advise you to ask for specific advice/feedback about yourself / your dating profile / etc. I’m happy to provide that if you want it, but an appropriate subreddit or facebook group would likely be better.
You say you spend a lot of time on dating apps “to no avail”—where are you getting blocked? Are you getting no matches? Are you getting matches but the conversations don’t lead to dates? Are you going on first dates but not getting second dates?
Getting no matches implies your standards might be too high or your profile/photos might suck.
No conversations implies that you might not be engaging women effectively or you might be engaging effectively but not want to seem pushy by asking for a date.
First dates but no second dates might imply anything from you smell bad to you come across weirdly to you’re just not going on enough of them.

mad 21 Sep 2022 3:16 UTC
10 points
0
on: What key nutrients are required for daily energy?
Uh, I don’t know where to begin. This is like, the entire field of nutrition.
Vitamin D does not need to be obtained from the diet, it is primarily produced in the skin (from cholesterol, which you don’t need to eat; your liver produces all you need from any food) after sun exposure. The amount of sun exposure required depends on the time of year, time of day, cloud cover, and amount of skin exposed. VitD can be obtained in the diet but pretty much only from fish and food that has been supplemented. I assume you are now taking high-dose supplements, because the amount in a typical multivitamin isn’t enough.
That said, fatigue is associated with iron deficiency, and if you menstruate there is a ~25% chance you aren’t eating enough to have optimum levels—look into a blood test. (If you don’t menstruate, you’re probably fine, but a blood test can’t hurt).
I am like 2 months away from having an undergraduate degree in nutrition, and I’m studying in Australia, so I recommend this website to you: https://www.nrv.gov.au/
It outlines all the nutrients (from carbohydrates/protein/fat to the vitamins and minerals) and gives the recommended dietary intakes for each. It describes the scientific basis for each, with citations.
This is a calculator you can use to get a ‘personalised’ recommendation for each nutrient: https://www.nrv.gov.au/nutrients-energy-calc
EDIT: Thinking about it a bit, is the question you actually meant to ask “what are common nutritional deficiencies that I might not know about”? That depends on many things, but Vitamin D would be #1 on my list.

mad 5 Sep 2022 3:22 UTC
3 points
0
in reply to: Jayson_Virissimo’s comment on: (Link) I’m Missing a Chunk of My Brain
Apparently the extent to which Phineas was affected by the injury is exaggerated, see: https://skeptoid.com/episodes/4744

mad 24 Dec 2021 1:35 UTC
4 points
in reply to: Centhart’s comment on: Help figuring out my sexuality?
What you are saying in all your comments is perfectly consistent with how I’ve heard people say about their experience as asexuals. Have a read of asexual literature, maybe post on a few asexual forums with your experiences.
At the end of the day, I am 100% sure there are people with similar experiences to you who call themselves asexual and also who call themselves allosexual (not asexual).
At the end of the days, these labels are a personal thing, like deciding how to cut your hair. There’s no right or wrong way, just what makes you feel good.
What links here?
- Help figuring out my sexuality? by Centhart (22 Dec 2021 20:28 UTC; 13 points)

mad 22 Dec 2021 23:37 UTC
34 points
on: Help figuring out my sexuality?
My advice is don’t stress too much about labels.
I’m a woman who dates in kink-adjacent circles, and I’m a dommy switch so I have seen a lot of subby guys’ profiles. You seem pretty normal, you seem like the sort of guy I date, down to the social awkwardness/lack of experience. I have a goddess kink so your specific fantasy is right up my alley. There are lots of women like me.
I’ve dated men who have been pretty normal but just didn’t enjoy vaginal sex, we still had sex but just not PIV. I’ve dated men with fetishes who also enjoyed sex.
If you WANT some labels, the different types of attraction might speak to you:
https://lgbtq.unc.edu/resources/exploring-identities/asexuality-attraction-and-romantic-orientation/
As you said about the painting, it may be that you are attracted to women in an aesthetic way.
The good thing about labels is that people don’t generally police them too hard because they’re never perfect; I myself identify as straight but it’s not a perfect label for me, just very very close.
If it makes you happy to call yourself asexual or demisexual or whatever, then do it, try it on. You can always change your mind later. Maybe try joining local ace groups and talking about your experience with them, or reading through relevant subreddits.