[HN Gopher] China Bans Flightradar24
       ___________________________________________________________________
        
       China Bans Flightradar24
        
       Author : imartin2k
       Score  : 226 points
       Date   : 2021-11-08 16:27 UTC (6 hours ago)
        
 (HTM) web link (theprint.in)
 (TXT) w3m dump (theprint.in)
        
       | novok wrote:
       | The Chinese government probably wants a local only edition of
       | this that they can control better, in typical China fashion.
        
       | jaywalk wrote:
       | > CCTV reported that Beijing Municipal National Security Bureau
       | found data-sharing poses a security threat to military aircraft.
       | 
       | FlightRadar24 (and indeed any flight "radar" that consumers have
       | access to) relies on ADS-B data, which is transmitted by the
       | planes themselves. Any sensitive military aircraft would (should)
       | not be transmitting this data, and so would not show up on these
       | services.
        
         | xyzzy21 wrote:
         | The US DOD uses a different system specifically for this
         | reason!
        
           | rjsw wrote:
           | Sometimes it leaves ADS-B enabled to send a message. During
           | the evacuation of Afghanistan there were B-52s over Kabul
           | that could be tracked on Flightradar24.
        
             | jjwiseman wrote:
             | Not to mention the Mi-17 (with possible CIA links) used in
             | evacuating the "Salt Pit" black site:
             | https://twitter.com/Gerjon_/status/1428809921156591620
        
         | dym_sh wrote:
         | unless army planes go undercover and need to transmit that data
         | to keep disguise of a regular civil aircrafts
        
           | queuebert wrote:
           | Does this happen?
        
             | _joel wrote:
             | I'd assume so, even in shipping, NASA recently disguised
             | the James Webb shipment to French Guiana as a commercial
             | vessel and set it's arrival destination somewhere in
             | europe. So it's highly likely this happens in military
             | context with flights too.
        
           | Kye wrote:
           | A plane that's obviously not what it claims to be to
           | experienced observers will only make people more curious.
           | 
           | edit: for example
           | https://news.ycombinator.com/item?id=29152224
           | 
           | It would be just another government plane, but they went and
           | made it interesting.
        
           | jjwiseman wrote:
           | There is at least one U.S. Marshals aircraft that seems to
           | intentionally broadcast a deceptive transponder ID. See https
           | ://twitter.com/tropicostation/status/145598271548065382...
           | and https://twitter.com/tropicostation/status/141546213651227
           | 852...
        
         | celticninja wrote:
         | Yes but it does allow people to track the private jets flown by
         | the Chinese government.
        
           | notahacker wrote:
           | The irony is Flightradar24 accepts requests not to display
           | sensitive aircraft and some of the other ADS-B aggregators
           | don't...
        
             | bellyfullofbac wrote:
             | But isn't telling a foreign entity "Hey, please censor
             | information of these planes" almost equal to telling the
             | jurisdiction of that entity "Hey, do you want a list of our
             | planes you should pay attention to?".
             | 
             | The Chinese government is involved with the big companies
             | there, so they must assume the same is true for the US
             | government and companies...
        
               | notahacker wrote:
               | Not really. They don't have to state that they're the
               | Chinese government when requesting the data is removed,
               | and I'm sure some of the aircraft already not displayed
               | are very boring aircraft with very boring owners.
               | 
               | It's not like the US government doesn't know where these
               | aircraft are already and have an abundance of ways to
               | identify whether they're "of interest" or not
        
           | fortuna86 wrote:
           | Bingo.
        
         | jjwiseman wrote:
         | There can be a bit more nuance to it than that. FlightRadar24
         | and other tracking sites do use ADS-B data broadcast by
         | aircraft themselves, but they also use other information. There
         | are other ways that aircraft that aren't broadcasting ADS-B can
         | still show up on a map.
         | 
         | 1. Mode S: Even if an aircraft isn't broadcasting its own
         | position via ADS-B, if it's using Mode S its position can be
         | multilaterated if you have a cooperating network of receivers
         | (which is what FR24, ADS-B Exchange, etc. have).
         | 
         | 2. TIS-B: An aircraft could be using Mode A/C, which generally
         | can't even be multilaterated, or it could have its transponder
         | turned off entirely and ATC can still use primary radar returns
         | to broadcast a synthetic ADS-B-type target for safety, so that
         | other nearby aircraft will see it show up on their traffic
         | displays. The data won't tell you what aircraft it is, but you
         | know where it is. And in fact, it's frequently possible for
         | experienced observers to figure out what kind of aircraft it is
         | and who's flying it based just on its track, speed, and
         | altitude. I frequently see contacts on ADS-B Exchange in the
         | Los Angeles area that are obviously fighters flying without
         | ADS-B or Mode S, showing up as TIS-B.
         | 
         | Military aircraft on sensitive operations can turn off their
         | transponders, and I don't know if China uses TIS-B, but I just
         | wanted to clarify that there is data besides ADS-B that gets
         | used, and that a network of receivers has capabilities that a
         | single receiver doesn't.
        
           | jjwiseman wrote:
           | Kinda relevant: Here's a thread about a group of aircraft
           | flying in the U.S. that were trying to hide their identities
           | by using the FAA's "Privacy ICAO Address" (PIA) program.
           | Under the PIA program, aircraft can broadcast ADS-B but they
           | don't use their real registration info, so theoretically
           | you're not supposed to be able to tie the aircraft to a
           | person or company:
           | https://twitter.com/lemonodor/status/1456377882582798338
           | 
           | But because it's still relatively rare for aircraft to use
           | PIA, and even more rare for a group of several aircraft to
           | use PIA and take off from the same airport and fly together,
           | they attracted the attention of a few people on twitter who
           | suddenly got very interested in these aircraft and who was
           | flying them. People quickly figured out where the aircraft
           | where flying to, and realized that airport had a public
           | webcam. As the jets landed, people confirmed the tail numbers
           | of these aircraft that were trying to fly under the radar, so
           | to speak.
           | 
           | The thread ends with the identity of the aircraft and their
           | owner having been discovered, some hypotheses about the
           | reason for the flight, figuring out which resort the
           | passengers were staying at, and... the airport having
           | apparently seen what was happening on twitter and sending
           | someone out to put a plastic bag or something over the webcam
           | to block everyone's view.
        
             | dylan604 wrote:
             | >put a plastic bag or something over the webcam
             | 
             | Kind of a 'closing the barn door after' kind of thing yeah?
             | Might. Would have been better OpSec to leave it running
             | until the _next_ event. Then turn it off prior.
        
             | easton wrote:
             | It seems like the money and time it would take to set that
             | up would be way more than just buying everyone tickets on a
             | commercial plane for that flight.
        
               | jfrunyon wrote:
               | Of course flying on a commercial plane would be cheaper.
               | They aren't flying on private jets because it's cheaper,
               | they do it because their shareholders are the ones paying
               | for it and they don't want to sit next to a plebe.
        
               | dylan604 wrote:
               | and the hassle of dealing with the public in an airport
               | vs rolling right up to the private plane, getting on,
               | taking off. The only thing easier is POTUS on Air Force
               | One
        
           | toomuchtodo wrote:
           | Iridium also has ADS-B receivers onboard the latest
           | satellites going up to enable global coverage, although I
           | don't have context as to data access and pricing.
           | 
           | https://aireon.com/resources/overview-materials/its-just-
           | ads...
        
             | papercrane wrote:
             | You can buy access to the data from FlightAware. I've never
             | been in a position to see the pricing, though I'm sure it's
             | expensive.
        
             | sorenjan wrote:
             | They're visible on Flightradar24. Look at the north
             | Atlantic, there's usually several of them at any time. The
             | satellite sourced data uses blue icons on the map.
        
               | wiedehopf wrote:
               | That's not Aireon data but rather ADS-C which is just
               | Iridium data link as far as i know.
        
             | andrepew wrote:
             | I believe for the satellites to pick you up you need ADS-B
             | antenna diversity (an antenna on the top and bottom of the
             | plane) which I don't believe is very common yet because it
             | has cost.
        
         | brian_herman wrote:
         | At least I can still see flightradar still in china.
        
         | jMyles wrote:
         | > Any sensitive military aircraft would (should) not be
         | transmitting this data, and so would not show up on these
         | services.
         | 
         | In addition to jjwiseman's comment that Mode S tracking and
         | TIS-B are still widely useful (something you can easily see for
         | yourself in many parts of the world, including around the 305th
         | Bomb Wing in Tampa (near my recent home of St. Pete), which are
         | a joy and marvel to watch), I want to add one more comment:
         | 
         | I don't think it's reasonable to take as granted that any
         | particular party (especially those which are taxpayer-funded )
         | "should" refrain from transmitting surveillance and telemetry
         | data. Rather, I hope we develop a society in which anybody who
         | is flying a large, fast, dangerous piece of metal through the
         | sky is required to report, via such an open standard, these
         | details for all to see.
        
       | bondolo wrote:
       | "a citizen with the surname Li had signed up"
       | 
       | Well that certainly narrows it down.
        
       | jmnicolas wrote:
       | Unless I misunderstand, I don't see the point: you can get this
       | data with a RaspberryPi and an antenna available everywhere (and
       | probably built in China).
       | 
       | Military aircraft that shouldn't be seen should just disable data
       | transmission.
        
         | blamazon wrote:
         | If I was a vendor in Shenzhen selling SDR modules to the
         | public, and I saw this come across the propaganda wire, I would
         | think hard about if it is still worth it to keep selling the
         | modules to Chinese customers.
         | 
         | China knows that direct control is hard to achieve at scale.
         | They know they can simply state their intentions and let the
         | chilling effects take over. Banning Flightradar24 is a
         | statement of intention that every one of their citizens can
         | see.
        
           | mianos wrote:
           | Any Realtek TV tuner USB stick can be used. They are for sale
           | everywhere in China.
        
           | jmnicolas wrote:
           | My question is what does it accomplishes for China? Foreign
           | armies and terrorists can still get plane positions, only
           | average citizen can't. What's the point?
        
         | jeroenhd wrote:
         | > Unless I misunderstand, I don't see the point: you can get
         | this data with a RaspberryPi and an antenna available
         | everywhere (and probably built in China).
         | 
         | I'm not sure about the relevant Chinese radio interception
         | laws, but I think the difference between DIY receivers and
         | Flightradar24 is that the website combines data from a great
         | many listening stations across the world. You'd need one hell
         | of an antenna to receive location data from a Chinese plane
         | from all the way over in the EU or US, but these websites still
         | allow us to see flight patterns above China.
         | 
         | > Military aircraft that shouldn't be seen should just disable
         | data transmission.
         | 
         | Permanently disabling ADS-B on military aircraft sounds like a
         | recipe for disaster.
        
           | vdqtp3 wrote:
           | It's literally flipping a switch.
        
       | tzs wrote:
       | OT: anyone happen to know what it means on FlightAware when a
       | plane is colored red?
       | 
       | I open FA when I hear a low jet, and recently I noticed that some
       | of them were red. The red ones were always NetJets Aviation
       | flights. Zooming out, I could see that there were red ones
       | scattered all around the US, and they all seemed to be NetJets
       | Aviation.
       | 
       | This lasted for at least a few days, but lately NetJets Aviation
       | flights have shown up in the same yellow as everyone else, and
       | now zooming I out I don't see any colored red.
        
         | jeroenhd wrote:
         | The FAQ [0] says:                   What do the color-coded
         | airport marker dots indicate?                  The color dots
         | represent the flight conditions at a particular airport from
         | the METAR (aviation weather report) when such data is
         | available:                      Purple: LIFR             Red:
         | IFR             Blue: MVFR             Green: VFR
         | 
         | I think that implies that planes get colored based on their
         | flight modes as well?
         | 
         | [0]: https://uk.flightaware.com/about/faq#metarcolors
        
           | imadethis wrote:
           | Pretty much 100% of all passenger/cargo jets will be flying
           | under IFR rules, so that wouldn't be the reason unless most
           | planes are red.
        
       | RattleyCooper wrote:
       | It's not worrying at all, that China acts like everyone who isn't
       | Chinese is out to get them or undermine them /s
       | 
       | Nobody who's done anything shady has ever acted like that in the
       | history of the world /s
        
       | speakspokespok wrote:
       | Speaking for the USA, the ADS-B data stream you see on
       | FlightAware's commercial feeds has military and police aircraft
       | data filtered, even if those aircraft are broadcasting that
       | information. While ADS-B data reception is public, certain data
       | types must be removed in your commercial offering per FAA.
       | 
       | Near me in Puget Sound / Seattle are two intl airports, several
       | military bases including a nuclear sub base, plus we're near the
       | US / Canadian border. Air traffic as you can imagine is very
       | interesting and includes state police Cessna's at night cruising
       | for people speeding on Highway 18, military transport through
       | JBLM (military base) but no fighter jet ADS-B. There's commercial
       | air traffic, hobby planes, private jets, hospital and news
       | helicopters. There's flight paths and local flight patterns. My
       | current mystery are the small, black, unmarked DHS (I think!)
       | helicopters that cruise Discovery Park lighthouse every few
       | hours. They don't show up on ADS-B at all. There's more but you
       | get the idea of how cool this all is. SDR is just wild. All you
       | need is a Pi 3 and the PiAware image, the antenna and the 1050
       | filter they suggest. PiAware has a local webinterface that shows
       | everything it's picking up but will be filtered later by
       | FlightAware.
        
         | DarmokJalad1701 wrote:
         | > Speaking for the USA, the ADS-B data stream you see on
         | FlightAware's commercial feeds has military and police aircraft
         | data filtered, even if those aircraft are broadcasting that
         | information
         | 
         | I have seen military aircraft on FlightAware before. This one
         | for example: https://flightaware.com/live/flight/SIKES85/
         | 
         | It was a pair of KC-46s practicing in-air re-fueling and were
         | actually visible from the ground.
         | 
         | Some other examples:
         | https://flightaware.com/live/flight/NITRO72/
         | 
         | https://flightaware.com/live/flight/BISON2/
         | 
         | Pretty sure these are fighter jets given the speed at which
         | they are maneuvering:
         | 
         | https://flightaware.com/live/flight/COBRA66/history/20211108...
         | 
         | https://flightaware.com/live/flight/COBRA44/history/20211108...
         | 
         | https://flightaware.com/live/flight/COBRA52/history/20211108...
         | 
         | You can basically check the flightaware pages for Air Force
         | bases and find these.
        
           | rootusrootus wrote:
           | Not sure about those last three being fighters. One of them
           | was going fast enough to be plausible, but the other two
           | spent the flight in the 200-300 mph range. That's not much
           | above stall speed for an F-16 or F-22, for example.
        
             | DarmokJalad1701 wrote:
             | Agreed that COBRA66 and COBRA52 seem to be pretty slow for
             | a fighter jet even though they were still flying loops at
             | over 150 kts in one case. COBRA44 though seems to be in
             | about the correct range.
        
               | jjwiseman wrote:
               | COBRA44 is a T-38 (trainer used to train fighter pilots):
               | https://globe.adsbexchange.com/?icao=ae00d6
               | 
               | COBRA51 and COBRA66 are thought to be Beech C-12C Hurons:
               | https://twitter.com/SkyCirclesR2508/status/14577732869353
               | 062... https://twitter.com/SkyCirclesR2508/status/1457792
               | 6990423859...
        
         | YeBanKo wrote:
         | > certain data types must be removed in your commercial
         | offering per FAA.
         | 
         | Can you link to source if it? Afaik everything transmitted by
         | ADS-B is public including military and le. FAA allows mil or le
         | to turn off ADS-B out if it can compromise their mission [1].
         | 
         | [1] https://www.aviationtoday.com/2019/07/23/new-rule-allows-
         | mil...
        
         | andylynch wrote:
         | Have you tried ADS-B Exchange? They don't use FAA data or apply
         | their filters.
        
         | matthewmcg wrote:
         | Unfiltered cooperatives like adsbexchange.com are also good
         | ways to see what's up there that might be filtered on FR24 or
         | FlightAware.
        
           | bokohut wrote:
           | This, TLDR other comments. Others do filter data and the
           | proof is in comparing in real-time all the sites along with
           | actually seeing the vehicle and its location in the sky as
           | some data can be delayed.
           | 
           | I do not claim to be a plane spotter but given where I live I
           | have picked up interest in the last several years after U.S.
           | president 45 was elected and even more now with 46. 46 goes
           | home nearly every weekend and the FAA flight restriction
           | circumference borders right over my house. I also have the
           | locational benefit of being inline with the flight path and
           | approach for Air Force N for 46s comings and goings by plane
           | which I have seen multiple times and I did see 45s helicopter
           | once flying over enroute to NYC.
           | 
           | Others may not be aware that there is the active deployment
           | of fighter jets and air refueling tankers that support this
           | FAA VIP air restriction. Since 46 has been elected and nearly
           | every weekend he is home we experience non stop fighter jet
           | thrust rumble at our location. One will not find these jets
           | on any public data plane location stream yet the persistent
           | presence of the air refueling tankers and the rumble from
           | jets burning fuel on the ready makes it obvious of the jets
           | presence for those in the know. Given the proximity to major
           | airports the air refueling tanker is listed on adsbexchange
           | and fly's in circles sun up to sun down topping off those
           | jets.
           | 
           | A few Sundays back we had pristine clear skys for both PV
           | collection as well as noob plane spotting. Using binoculars
           | on a tripod and sky scanning based on the tankers locations I
           | believe I saw the back side of a F22 coming in to top off. I
           | did get a picture about an hour later of an unknown jet type
           | refueling off the air tanker after months of trying, I just
           | smiled.
           | 
           | As to the point of this "China" ban I personally know the
           | value of such data in my own accomplishments as I see it akin
           | to social engineering. Granted it is not war time so the
           | tanker is broadcasting but I find it an oversight by those in
           | charge to advertise where mother goose is as the goslings are
           | never far behind.
        
         | C19is20 wrote:
         | Cessna's looking for speeders. I wonder what the ROI on that
         | is: I'm guessing that's not all they do.
        
           | kortilla wrote:
           | What's the ROI on responding to domestic disturbances in low
           | income neighborhoods?
           | 
           | What a silly way to look at safety money.
        
             | ev1 wrote:
             | That depends on how much you think a human life is worth,
             | disappointingly.
        
               | robocat wrote:
               | I would like to see some numbers for implied value of
               | life by some of the decisions we make (driving at speed,
               | extreme sports, anything fun but risky), especially the
               | implied value for yourself versus others like
               | pedestrians.
        
           | LorenPechtel wrote:
           | The one place I've seen a Cessna on speeder patrol it
           | certainly paid for itself. There was a spot where an
           | interstate cut through an Indian reservation. The speed limit
           | was set to 65 mph even though the road was better than that.
           | 
           | A bird in the sky plus more cops than I would have thought
           | they had were a frequent occurrence there, pulling over
           | basically everyone who wasn't aware of the speed trap.
           | Certainly worth it.
           | 
           | One day they raised the limit to 75 which is far more
           | appropriate--I've never seen the plane since, I've seen one
           | cop a couple of times hiding behind the crest of a hill.
        
             | themitigating wrote:
             | "Even though the road was better than that"
        
               | baq wrote:
               | Where I live, people flying past you at 100+mph is a
               | common occurrence on the autostrada. (Yeah not US.) Speed
               | limit is 80ish.
        
           | [deleted]
        
           | hippocombinator wrote:
           | Aren't speeding tickets known to be really big income for
           | local governments?
           | 
           | They can be hundreds of dollars; I'm sure it can work out
           | financially if they can hand out enough, which seems likely
           | from an airplane.
        
             | loeg wrote:
             | Can't give a specific driver a ticket from an airplane. I
             | thought the main function of the planes was to follow
             | extreme speeders, which has to be revenue negative -- just
             | because there are so few and it takes so long -- but maybe
             | a justified expense.
        
               | shagie wrote:
               | They are able to identify speeders without radar using
               | fixed distance marks on the road and timing cars
               | traveling between those marks. At that point, they are
               | then able to give information about the car to the police
               | on the ground for them to be pulled over.
        
               | jjwiseman wrote:
               | These days they all pretty much have systems like the
               | Churchill/Shotover Augmented Reality Mapping System (ARS)
               | which will give them target vehicle speed automatically.
               | Even news helicopters use similar systems[1].
               | 
               | 1. https://shotover.com/videos/videos/kabc_tv_air7hd_with
               | _xtrem...
        
             | mywittyname wrote:
             | There are entire towns who can only afford to have a police
             | department because of their ability to write traffic
             | tickets.
        
           | EdwardDiego wrote:
           | I used to live in a remote mountain village, located on one
           | of the main highways across our central mountain range. 8km
           | or so of the highway leading into the village was narrow and
           | winding with no shoulder - the road lines were cut in the
           | horse and coach days, so not designed for cars. It was
           | surrounded by forest, often with bluffs on one side and a 20m
           | drop on the other.
           | 
           | People crossing the centre line on blind corners because they
           | were driving too fast were a real hazard on that section of
           | road.
           | 
           | One summer (when the road was busiest) the Police ran an
           | operation where a helicopter observed the road, and
           | identified vehicles cutting corners, who were then pulled
           | over outside the 8km stretch where it was safe to do so by
           | waiting patrol cars.
           | 
           | They only ran it for a couple of weeks, but the calming
           | effect of it on bad driving on that stretch lasted months, it
           | was awesome.
           | 
           | So the Cessna might not be about making money, and more about
           | the potential presence of the Cessna changing driving
           | patterns increasing safety.
        
             | stopagephobia wrote:
             | "People will behave well if they think Big Brother is
             | always watching so let's make them think that"
             | 
             | Remember when you could leave your house and not get
             | recorded? I miss that.
        
             | kmonsen wrote:
             | In Norway they put one of those radar boxes with a camera
             | in places like this. They even put a sign a mile before
             | saying there is going to be a box since the objective is
             | not to catch people but to make the average traffic slow
             | down.
        
               | ChrisMarshallNY wrote:
               | In the US (at least in NY), traffic tickets are
               | considered income -especially in Manhattan. Some
               | jurisdictions actually plan budgets on it. The same with
               | civil forfeiture.
        
               | xenophonf wrote:
               | Not to be outdone by NYC, this happened in Chicago, too:
               | 
               | > _A Tribune examination of overturned red light tickets
               | revealed evidence that the city of Chicago has quietly
               | cast a wider net to snare drivers since switching camera
               | vendors earlier this year amid a bribery scandal._
               | 
               | > _A before-and-after analysis of photographic evidence
               | and interviews with experts suggests the transition to a
               | new vendor last spring was accompanied by a subtle but
               | significant lowering of the threshold for yellow light
               | times._
               | 
               | https://www.chicagotribune.com/news/ct-red-light-camera-
               | yell...
        
               | mywittyname wrote:
               | This happened all over the US:
               | 
               | https://www.foxnews.com/politics/ohio-town-must-pay-back-
               | mil...
        
               | nieve wrote:
               | The New York Times has been running a series on traffic
               | stops focusing on reasons for the high death rate among
               | motorists who are pulled over, but they also did this
               | long and infuriating piece on the funding issue. It was
               | actually somehow even worse than I expected:
               | https://www.nytimes.com/2021/10/31/us/police-ticket-
               | quotas-m...
        
           | edrxty wrote:
           | They usually fly something like a 206 or 182 with a Flir
           | gimbal and two people on board. Those types cost between $120
           | and $200 an hour to operate plus whatever the costs of the
           | gimbal are (mind that the gimbal may cost as much or more
           | than the host aircraft).
           | 
           | The pilot and sensor operator are paid so that's another
           | $100+/hr after benefits and such are paid.
           | 
           | I'm guessing they just do it to subsidize the aircraft and
           | give it something to do between calls when it's on station.
           | The aircraft costs money just sitting in the hangar so it'll
           | help justify the costs.
        
             | PhantomGremlin wrote:
             | There's a "Portland Police Bureau" activity going on right
             | now, using a C182. I think they are following a car on
             | various local highways.
             | https://globe.adsbexchange.com/?icao=a1d296
             | 
             | But that's misleading. I've been told that the FBI usually
             | pilots that particular aircraft. So the ADSB "owner" could
             | be someone else.
             | 
             | This also factors into economics. Stuff like FLIR might be
             | expensive to local police agencies but that cost is totally
             | irrelevant to the Federales. Same with salaries. The Feds
             | are already getting paid. The incremental cost is $0.
             | 
             | Most of the time this particular aircraft is observing
             | various intersections in Portland. E.g. pursuing fleeing
             | perps or monitoring street racing. Gang violence in
             | Portland is out of control and there has been a public
             | announcement that the FBI is helping.
        
           | JCharante wrote:
           | Even if they don't generate money from that, catching people
           | speeding is a public service. If one disagrees with the idea
           | that speeding is bad, then why don't we raise speed limits
           | until the speeds deemed "reasonable" at under the limit.
        
             | TigeriusKirk wrote:
             | OK, let's do that.
        
               | dymk wrote:
               | 60 is plenty on Highway 18, especially during these wet
               | fall and icy winter months
        
               | zionic wrote:
               | 60 as a limit on any controlled access road is an
               | absolute joke.
        
               | shadowgovt wrote:
               | It turns out to be more difficult than people want.
               | 
               | to be certain, some speed limits are low for bad-science
               | reasons. But the other issue is that the speed limit
               | isn't set for the average case; it's set for the safety-
               | limit case. As one highway engineer's blog put it
               | colorfully (paraphrasing from memory): they aren't set to
               | keep your decently-well-maintained 4-door sedan with
               | tires installed this year on the road; they're set to
               | keep the 18-wheeler driven by a sleep-deprived trucker at
               | night during a light drizzle on the road when one of
               | their tires blows.
               | 
               | Variable speed limits that adjust automatically with
               | weather and lighting conditions can help, but the signage
               | to indicate them costs money... Way more money than a
               | static metal road sign.
        
             | rwmj wrote:
             | Sure, but fixed cameras along the route must be a lot
             | cheaper than the plane.
        
               | mywittyname wrote:
               | They are illegal in a lot of states. I no small part
               | because of the egalitarian nature of them. Government
               | officials are getting ticketed and they get the same
               | treatment as the rest of us.
               | 
               | Some states have ruled them unconstitutional.
        
               | ceejayoz wrote:
               | They're on Waze five minutes later.
        
               | echelon wrote:
               | I'm a staunch privacy advocate, but we have thousands of
               | people in my state dying a year from automobile
               | accidents. (On par with gun deaths, a figure which
               | includes 60+% suicides.)
               | 
               | I'm not sure I'd fight it if we lined the entire
               | interstate highway system with plate detectors.
               | 
               | If your average speed is above a reasonable limit (80mph
               | on low density straightaways?), then you receive a ticket
               | at a rate multiplied by the duration of infraction.
        
               | kmonsen wrote:
               | Norway and Finland fines proportional to your yearly
               | salary. Of course there are some problems with that, but
               | in general I like that system more.
        
               | closeparen wrote:
               | Where there's a lot of speeding to catch is low density
               | straightaways marked 35.
        
               | kccqzy wrote:
               | You can make these cameras so dense that there is very
               | little opportunity for speeding in between two cameras.
        
               | guruz wrote:
               | No need for so many cameras. You only need two :-)
               | 
               | https://en.wikipedia.org/wiki/SPECS_(speed_camera)#Simila
               | r_s...
               | 
               | https://en.wikipedia.org/wiki/Speed_limit_enforcement#Ave
               | rag...
               | 
               | (Sorry for the nerdy nitpick)
        
               | occamrazor wrote:
               | This is essentially the way it works in Switzerland. On
               | motorways there are speed cameras every few kilometers:
               | even with an app to warn you, it's not worth trying to
               | speed between cameras.
        
               | kmonsen wrote:
               | Oh man I got so many speeding tickets in Switzerland
               | (like 5 in two years). They were all super minor like $50
               | or something?
               | 
               | I heard it does not apply to all cantons, the Italian
               | ones speeding is more OK.
               | 
               | All that being said I really dislike the US system where
               | you can pass a police car driving 75 on the 101 and he
               | doesn't care. There has to be some enforcement of the
               | rules.
        
               | robocat wrote:
               | When you travel in a country where limits are harshly
               | enforced, driving is wayyy more relaxing because of the
               | reduction in speed variation (most people travelling at
               | the stated limit) and no crazy overtaking manoeuvres
               | (idiots don't just harm themselves). That said, I'm not a
               | fan of draconian speed limits.
        
               | ceejayoz wrote:
               | > All that being said I really dislike the US system
               | where you can pass a police car driving 75 on the 101 and
               | he doesn't care. There has to be some enforcement of the
               | rules.
               | 
               | The US system is a probable cause generator.
        
               | 404mm wrote:
               | That's simple. Just do one camera at the beginning, one
               | at the end and you can get average speed by simple math.
               | While it allows you to go above the speed limit, you also
               | have to slow down to "lose" that earned time so at the
               | end it averages back to speed limit. Go ahead and
               | advertise this speed trap well because the more people
               | understand how this works the better.
        
               | jonathankoren wrote:
               | So? Wouldn't people that know the cameras are there drive
               | slower than the people that don't? From a public safety
               | point of view, known cameras are more effective at
               | limiting speed than unknown ones.
               | 
               | Reducing lane width is also shown to be a very effective
               | speed control methodology, that does not require police
               | enforcement.[0]
               | 
               | Or are you concerned about a loss of local and state
               | revenue? Seriously, the use of police for revenue
               | generation, rather than public safety is an open secret
               | among police and local governments.[1][2][3]
               | 
               | [0] https://nacto.org/publication/urban-street-design-
               | guide/stre...
               | 
               | [1] https://harvardlawreview.org/2015/04/policing-and-
               | profit/
               | 
               | [2] https://www.policechiefmagazine.org/generating-new-
               | revenue-s...
               | 
               | [3]
               | https://www.theatlantic.com/national/archive/2014/12/the-
               | ben...
        
               | Zak wrote:
               | Good. If it's actually important that people drive slower
               | in that area, everybody knowing there are speed cameras
               | will have that effect.
        
               | oh-4-fucks-sake wrote:
               | Looking at you:
               | 
               | - Crotch rockets (driven by dudes in jorts and a t-shirt
               | flapping in the wind)
               | 
               | - Dodge chargers w/ aftermarket exhausts
               | 
               | - BMWs with iridescent vehicle wraps
               | 
               | - Lifted pickup trucks with _massively_ oversized tires
        
               | cheeze wrote:
               | This reads like a Reddit comment.
        
               | ceejayoz wrote:
               | If everyone guns it right after passing the camera,
               | you've potentially made things _more_ dangerous.
               | 
               | Aircraft allow for a "you could get caught at any time"
               | deterrent that cameras can't unless you put them
               | literally everywhere.
        
               | Gwypaas wrote:
               | They still increase the safety by limiting the speed in
               | for example an exposed intersection.
               | 
               | On the other hand you can go the average speed route
               | instead.
               | 
               | https://en.wikipedia.org/wiki/Speed_limit_enforcement#Ave
               | rag...
        
               | megablast wrote:
               | This is such an insane take.
               | 
               | The speed limit is for everywhere for safety. They faster
               | people go the more dangerous it is.
        
               | sokoloff wrote:
               | The US national speed limit was imposed as a fuel economy
               | measure not a safety measure.
        
               | jonathankoren wrote:
               | Actually, people tend to drive at the speed that is safe,
               | and traffic engineers set the limit at about the 85th
               | percentile of the observed speed. Maximum limits on safe
               | roads are usually lower than the observed speed, and so
               | serve no purpose from a safety perspective.
               | 
               | Traffic calming techniques like narrower lane widths and
               | widths are shown to be more effective than police
               | enforcement. The "downside" of these methods are that
               | they're actually effective at controlling speed, and thus
               | are a revenue loss.
        
               | Edman274 wrote:
               | Not the person you replied to, but I really feel like
               | enforcement must be a pretty substantial part of what
               | stops people from speeding and driving recklessly, given
               | that traffic enforcement has been de-emphasized since the
               | start of the pandemic and the number of road fatalities
               | has gone up more than 7 percent, even though the actual
               | number of miles driven has gone down.
               | 
               | https://www.nhtsa.gov/press-releases/2020-fatality-data-
               | show...
               | 
               | If people drive at whatever speed they think is safe,
               | then why would the aggregate number of people dying on
               | roadways ever go up when miles driven by the same
               | population goes down? Here are the possibilities:
               | 
               | 1. Driving has become more risky due to external,
               | uncontrollable factors, like weather or road changes that
               | motorists can't account for or
               | 
               | 2. People are modifying their behavior.
               | 
               | Why would they modify their behavior? The roads haven't
               | changed. The speed limits haven't changed. What has
               | changed? More people are dead because of extreme speed
               | and reckless driving on roadways, which kind of suggests
               | that traffic enforcement did at least prevent some of
               | those deaths.
        
               | xorcist wrote:
               | > Actually, people tend to drive at the speed that is
               | safe,
               | 
               | That not remotely true in any part of the world I've
               | visited so far.
        
               | konschubert wrote:
               | The cameras are more effective if people have to expect
               | them everywhere, because then they will (hopefully) stick
               | to the speed limit everywhere.
        
         | jjwiseman wrote:
         | Sorry if I'm being pedantic, but a lot of people do think that
         | all military and police aircraft are filtered by FlightAware,
         | FlightRadar24, etc., and that's not true. Right now I can find
         | several military and police aircraft flying in Southern
         | California on both FA and FR24.
         | 
         | As far as I know, the FAA doesn't ask anyone to filter any
         | types of aircraft or data. They do have a program, LADD[1]:
         | "Aircraft owners or designated representative may request
         | limiting aircraft data displayed (formally referred to as
         | blocking) or unblocking of flight tracking data." If you use
         | FAA data I believe you must honor the LADD list, but as far as
         | I know owners have to submit every registration number or call
         | sign that they want blocked (and that list has even been
         | FOIAed[2]). It's always possible that a flight tracking site
         | might decide they want to voluntarily block some type of
         | aircraft, but so far there doesn't seem to be evidence of that
         | that I know of.
         | 
         | [1] https://ladd.faa.gov [2]
         | https://www.muckrock.com/foi/united-states-of-america-10/faa...
        
           | natch wrote:
           | Thanks, good information.
           | 
           | >If you use FAA data
           | 
           | I was under the impression that FlightRadar24 uses crowd
           | sourced data collected by users with radio receivers managed
           | by Raspberry Pi if I recall correctly?
           | 
           | That doesn't mean that they don't use FAA data, I just don't
           | know that they do. And that's only addressing one of the two
           | services you mentioned, of course.
        
             | touisteur wrote:
             | FR24 uses radars and multilat streams too in some countries
             | iirc. Not all aircrafts have adsb but FR24 sees much more
             | aircraft than ADSB adoption rate should show.
        
         | verst wrote:
         | Are you feeding data to FlightAware for the free Enterprise
         | Subscription?
         | 
         | By the way I'm in Ballard (near Discovery Park) and do notice
         | those helicopters too. Whatever they are - they seem to usually
         | originate at KBFI which is where I'm currently doing my PPL.
         | 
         | Can you pick up both ADS-B and VHF radio with your setup or
         | would VHF require other hardware?
        
           | buildbot wrote:
           | Small world! I too live in Ballard and have been super
           | curious what these have been up to, they fly pretty low and
           | have a lot of hardware hanging underneath them.
        
           | jeffrallen wrote:
           | Different antenna. ADS-B is at 1090 MHz, and VHF air comms is
           | more around 121-135 MHz. The same SDR radio can tune those
           | two bands, but an antenna that works well for one would work
           | poorly for the other.
        
       | qwertyuiop_ wrote:
       | > _Chinese Weibo users are also asking why the country hasn't
       | 'recovered' Chumi Gyatse waterfall in Arunachal Pradesh from
       | India. Some suggest occupying it._
       | 
       | Hey USA there is some sweet little territory in Canada lets ask
       | our government to occupy it.
        
       | dirtyid wrote:
       | PRC air corridors are concentrated in coast, commercial and
       | military aviation are heavily intermixed because it's where
       | population and security considerations are. Does not take much to
       | capture a lot of data for useful analysis.
       | 
       | Somewhat related, Ministry of State Security commented on 3
       | security breaches to Xinhua recently. Case #3 was meteorolgical
       | observation equipment setup near sensitive military base that
       | sent data to overseas org. Insinuation seems to be it was part of
       | crowdsource intel gathering for commercial purposes that
       | ultimately had links to foreign military. Open source intel OSINT
       | has been blowing up, so PRC looking to secure data.
        
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