The LED Traffic Light and the Danger of "But Sometimes!"
Technology Connections7 HN recommenders · 2019–2024
4.2M views · explainer · evergreen · Uploaded 2018-05-14
Technology Connections explains how LED traffic lights, which do not melt snow, drew complaints and were blamed for accidents. He uses it to illustrate the 'but sometimes' fallacy against new technology.
Cited constantly as the name and example of the 'but sometimes' argument, where edge cases are used to resist better technology such as EVs and solar.
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16 comments from Hacker News
I watched a YouTube video [0] this morning which actually does a fantastic job of explaining the pros and cons of LED-based traffic lights. Short answer: it's complicated. [0]: [VIDEO]
This is a classic case of “But Sometimes” [1]. I guess sometimes lazy loading of images can be frustrating, but most of the times it’s not. 1: [VIDEO]
The one on traffic lights is way more interesting than it sounds! Everybody should check it out. There's also a really interesting point he makes at the end that applies to something a lot of people on HN might relate with [VIDEO] The toaster one is alright, it kinda bothered me when he said there was "literally NO reason" to design something the way it was (I think it had to do with the position of the coils) - obviously there is, it's probably just not a reason he'd like (cost, ease of manufacturing, etc). It makes me wonder if there was other info he skipped on because it "wasn't important" or "stupid". That's a pretty minor point though, overall his videos are very good.
Technology Connections has a great video on LED traffic lights and how the concern about snow was overblown: [VIDEO]
Your coin flip is in a vacuum though. What is this innovation replacing? Did I previously have to roll a 100-sided die? If so, that coin flip sounds really damn good. I feel like Technology Connections did a better approach to the same topic of innovation: [VIDEO] The idea is "But Sometimes". That is, this new innovation is great in all these areas, but sometimes it's worse. That then becomes a locus for the FUD campaigns -- justified or not. It's also the same kind of thing heard in "no one was ever fired for picking IBM". Fear of an unknown potentially bad outcome outweighs all the known bad outcomes which are improved by the innovation.
I'm reminded of a Technology Connections video about what happened when his town switched from incandescent to LED stop lights < [VIDEO] > Of course, while I was looking that up I found out he made a video about sodium vapour lights! < [LINK] >
>Apropos of nothing... I also remember a story about a northern country replacing traffic lights with LEDs and then spending even more money adding heaters because the old lights were naturally warm, and melted any ice that stuck to the lights. Can't find a link to it at the moment. The Technology Connections channel on YouTube has an excellent video on this, called 'The LED Traffic Light and the Danger of "But Sometimes!"': [VIDEO]
You may be interested in the video The LED Traffic Light and the Danger of "But Sometimes!" by Technology Connections: [VIDEO]
[VIDEO] One can think of all sorts of tail cases where some better technology is worse, but we should be careful not to let the tail cases cloud our overall analysis of a technology. "I might not be able to escape if my whole town was on fire" is also an argument against virtually all public transportation - but clearly should not be used as a reason to disregard public transportation.
Finally! Someone finally said "hybrid", thank you! Every thread about EVs is just like the ~discourse~ about LED traffic lights. [1] "We must stop making pure ICE cars" "But pure EVs aren't ready" "But we must stop making pure ICE cars!" "But pure EVs aren't ready!" Back and forth for _literally 20 years_ in which this little-known Japanese company, Toyota, has been producing an insanely popular line of hybrid sedans called "Prius". [2] I live in a small town and I can't really drive anywhere without seeing at least one Prius. They are everywhere. The used ones are not super-expensive, either, especially compared to a pure EV that needs a bigger battery. Hybrids have been viable for _twenty years_ and people are still debating ICE vs. EV. Plug-in hybrids are now becoming more common, and even big pickup trucks are talking about mild hybridization. And a Prius can go 500 or 600 miles on a tank and then just refuel. A pure EV means no spontaneous road trips. Not a problem with any hybrid. Pure ICE should be out of the picture for 50% of drivers, but we are still using pure EVs as a weak man [3] to pretend that ICE cars are still viable in the post-Prius-plugin era. It makes me a little mad. [1] Technology Connections made a video on this ~discourse~ and how dumb it is: [VIDEO] [2] [LINK] [3] [LINK] Like the Nissan Leaf. Short range, cheap, bad in winter. No excuse to not talk about Priuses.
The angry faces are likely a knee-jerk to what other people perceive as a "but sometimes!" response. [VIDEO] Not exactly applicable of course, but I'm just trying to give you an idea of where I think the disconnect comes from. Honestly, I get it. How many people ask about the ethical concerns when it comes to having traditional utilities hooked up to their home? I've honestly never once thought about what my particular power company does to the environment.
Common trope everywhere honestly. Technology Connections speaks of it in the "but sometimes!" video [VIDEO] where LED lighting in traffic lights is meeting resistance¹ because sometimes it freezes/snows over. It's efficient, so no more heat to keep itself snow-free. Oh no, says the general public, we can't install that! Of course a little resistance heater is primitive technology, cheap to add, and it takes about two brain cells to realize that sometimes not being better than incandescent is still better than always using incandescent, yet still it's apparently a thing to work through. Not a problem exclusive to HN ¹ edit: I had not realized the irony here while writing this :-)
Technology Connections: [VIDEO] What's worse is that he points out you could have a lighting system with integrated defroster that only gets turned on when it's super cold, and you're STILL using less energy overall.
Let me reframe this. What we're saying to do is stop using C string manipulation such as strcat, strcpy, etc. Particularly, I'm saying simply don't use C-style null terminated strings until you actually go to call a C ABI interface where it is necessary. The argument against this is that you might call something that already internally does this, to your inputs directly, without making a copy. Yes, sure, that IS true, but what this betrays is the fact that you have to deal with that regardless of whether or not you add additional error-prone C string manipulation code on top of having to worry about memory ownership, mutation, etc. when passing blobs of memory to "untrusted" APIs. It's not about passing the buck. Passing a blob of memory to an API that might do horrible things not defined by an API contract is not safe if you do strcat to construct the string or you clone it out of an std::string or you marshal it from Go or Rust. All this is about, is simply not creating a bigger mess than you already have. Okay fine, but what if someone hates C++ and Rust and Go and Zig? No problem. There are a slew of options for C that can all handle safer, less error-prone string manipulation, including interoperability with null-terminated C strings. Like this one used in Redis: [LINK] And on top of everything else, it's quite ergonomic, so it seems silly to not consider it. This entire line of thinking deeply reminds me of Technology Connection's video The LED Traffic Light and the Dan
The exact issue you describe was a problem in a recent urban fire in the Netherlands though [1], the fire could not be properly extinguished under the embedded solar panels in the roof and spread further than it would have otherwise. Having these corner case be an over-focus of an overall better technology is a bad human habit though [2] [1] [LINK] [2] [VIDEO]
I love Technology Connections' take on this line of argument [0]: > When there's a new innovation which changes how we do things for the better, its benefits are obvious. ... However when the "But Sometimes" rears its ugly head, people tend to freak out. Suddenly all those benefits go away, because in this one particular facet of stoplight functionality, the wasteful and maintenance-heavy incandescent lamp is accidentally superior. Suddenly, when a new solution presents a new problem, all we think about is the problem. Yes, there are problems that exist with solar that don't exist with other electrical generation systems. That is not, by itself, evidence that solar will not be sufficient by itself as we solve those problems, and it's not a good reason to slow adoption of a piece of technology that is better in almost every way. Everything suggests we're going to fix the "but sometimes"—as others have noted there are many different paths being successfully explored at this point—and everything suggests that solar will still be both cheaper and better for the environment even when you factor in the fix. [0] [VIDEO]