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Cell phones used to track traffic 193
scm alerted us to a story in the San Jose Mercury News about some new technology which uses the reflected signals from cell phones to map traffic patterns. But it also seems to be able to track individual users as well by mapping those reflections to their physical location. Wonder which use will be the most "valuable"?
Re:This is highly unreliable (Score:1)
This is a really stupid idea... for LA (Score:1)
As for being able to "see" a vehicle pulled over on the pavement, you should know better. A sensor grid with 1/2 mile resolution will detect "rubbernecking" and tell you where the accident is, and the smount of traffic in the next 1/2-mile long section will tell you if any lanes are blocked, but you can't tell what kind of accident it is until (a) an officer shows up and radios it in, or (b) a cab-driver radios it in, or (c) a civilian calls in on a cell phone.
As for Baltimore, DC, Atlanta, Boston, NYC, Hartford (oh God... not Hartford!), the cities all have major traffic problems every day, and to my knowledge, there's no system in place to gauge it yet. There are radar guns on overpasses on sections of I-95S, but not enough to establish the kind of resolution that a grid of cell phones would provide.
I agree that LA's system is cool, but think about the future and the economics of the situation before you flame any new large-scale project.
--Jurph
(engineer by trade, geek by the grace of god)
Re:I don't see the big whoop about this. (Score:1)
Which is cheaper:
1) [Manpower to dig holes all over Boston and place sensors + time lost to detours + wiring a solid-state sensor grid into a computer + having to do it all again for each new section of roadway] * [resolution of the sensor grid]^2
OR
2) Buying a data collection system (computer, antenna, keyboard, monitor... mouse) that reads data from a satellite that's *already paid for*, and letting your citizens buy the sensors (phones)?
Come on now. Always think of infrastructure, cost to implement, future growth, and all of the real ugly real-world variables before flaming any large-scale project.
Jurph
Mechanical Engineer / Professional Bone Head
Re:Hook up to street lights (Score:1)
Nipok Nek
This is already being done (Score:1)
"It" has no idea whose phone... (Score:2)
(Just what you need - a cell phone call to distract you as you approach the turn behind which traffic is stalled...)
Seems to me that makes it obvious that the system knows perfectly well where each customer is, indexed by the phone's identification.
The cells have always been able to locate you within a couple miles - by signal strength. This was necessary to select the cell that handled your calls. A little hardware and software upgrade to each cell makes it possible to know your location within feet.
Knowing your location within miles is enough for phone calls, but not particularly useful to the police for tracking or apprehension. Knowing it within feet serves both purposes.
But knowing it within feet requires a hardware and software upgrade to essentially ALL the cell base stations - an upgrade that isn't necessary for their mission. That CO$T$.
So the government is mandating the instalation of the extra equipment. And they're looking for an excuse to make it palatable. Traffic statistics is their latest trial balloon.
I don't know what it's like where YOU live. But here in the S.F. Bay area there are already cameras watching traffic along all the major freeways and many non-freewayintersections (and which were often rotated to look at the surrounding neighorhoods, until it was noticed and commented on), under-pavement speed sensors ditto to control the metering lights, regular helicopter patrols during rush hours (which is much of the day here) by both the police and services feeding the radio stations, and police helicopter patrols much of the night.
All that confiscated money and property has bought a LOT of "cop equipment".
They need more traffic info from an expensive forced hardware and software tap on the cell phone systems about as much as Custer needed more Indians. (And how DO you separate "traffic congestion" from people with cell phones walking?)
But for tracking a suspect - or anyone else they don't like who happened to have a cellular phone - it's ideal.
A system that measures the location of the phones closely enough to monitor traffic - and call the phones of particular people who are approaching "traffic congestion" - can provide such tracking information on individuals, with no more than a minor software addition at a central site. Nothing is detectable outside the site except the polling of the cell phones - and the "traffic" application give them an excuse for that.
Anyone who tries to capture and reverse engineer the central site software to audit it for individual-tracking capability can expect the same treatment as Mitnick. So don't expect to find out about the individual-tracking capability until it's been in regular use for so long that they don't mind exposing it.
By the way: Did you know that some of the popular cell-phone models can be turned into room bugs by remote control?
Re:Problem is people yapping on cell while driving (Score:1)
That's not necessarily correct. I recall some studies having been done that indicate that the way people pay attention is different when talking on the phone as opposed to talking personally. The study tracked how much time cell phone users spent looking at the road ahead of them.
Presumably this depends on the individual. The study also suggests that having a hands-free device does not really help this problem. I am all for banning cell phone use by drivers while a vehicle is in motion.
Yeah. I know - should have the url for that, but I don't :-)
Tracking congestion... (Score:4)
I stand corrected. (Score:1)
Before you say No Way. (Score:3)
Re:What illegalization? (Score:1)
Re:Here's your "answer" (Score:1)
I don't see the big whoop about this. (Score:2)
http://www.startribune.com/news/traffic/cgi/loa
Bone heads will always find a more expensive way to do things when they can get money.
Re:I don't see the big whoop about this. (Score:1)
Re:Pretty unreliable tracking (Score:1)
Except that there is some overlap between cell antennas - if you have three and can gauge range by signal strength you can triangulate a position quite easily.
That's about as easy as it gets. Back in the CB days we used this find the bastards with the 200W transmitters who kept talking over the people who actually had something to say.
Hol.
Monitoring (Score:2)
Let me pose a different perspective.
First, regarding the cellular phone tracking stuff. Well.... You *are* using a phone that *broadcasts* over RF, which is an inherently *public* medium, and physics says there are ways to locate you if your signal can be isolated. So...scientifically speaking.. you do *NOT* have a reasonable expectation that your location is hidden. Now.. yes, the telco records that say what the signature of your phone is, your ESN, things like that.. should *ABSOLUTELY* be private. That's beteween you and your cel provider... but aside from that.... anyone with the right gear can know that a) someone is using a phone nearby and b) where they are.
So.. should this information be in the hands of the government only? Traffic reporters only? No...
it should be publicly available to anyone. ie: how many calls are going on I98? Hwy#4? How dense? Sure... as long as the database is *publicyly funded* and *publicly* available, and not monoploized.
Re:Pretty unreliable tracking (Score:1)
Relative signal strength has one disadvantage - it is affected by the number of buildings in the line of sight between the phone and the receiver.
However, one of the Danish GSM operators offers a product where the rate is halved at the phones home address. As far as I know, the location is based on distance from the closest three GSM cells. The measuring, which apperantly has a resolution of 10 meters, is found by timing the signals exchanged between phone and antenna during signal-strength evaluation.
Re:Only when the phone is completly active? (Score:2)
Digital phones only receive, except when they periodically send out signals to keep things working right, let the system know where they are, etc.. (one reason you get SOO Much more battery life out of a phone in digital mode)
Here's your "answer" (Score:1)
``It has no idea of whose phone it is or the number,'' he said. ``Compare it to a helicopter flying overhead monitoring traffic. It can see all the cars and how fast they're moving but has no idea who is driving that car. It just sees the traffic.''
So there you go, all you paranoid fanatic peoples can rest easy now.
Not really (Score:2)
It requires that users have a new phone equipped with the GPS technology but allows users to turn the locating system on and off at their leisure, bringing home the issue of privacy for the cell phone user.
With U.S. Wireless' system, the phone is always being tracked, Cunningham said.
``It's constantly monitoring location,'' Cunningham said. ``With ours, it's only working when you want it to. You push the button when you want to be found.''
Brunato says the RadioCamera system doesn't recognize the phone user for traffic management purposes.
``It has no idea of whose phone it is or the number,'' he said. ``Compare it to a helicopter flying overhead monitoring traffic. It can see all the cars and how fast they're moving but has no idea who is driving that car. It just sees the traffic.''
Sure, you Americans have all reason to be paranoid about everything, I grant you that. But every technology has potential to be applied to both "good" and "evil". This one seems useful enough for you guys to take the risk.
Me, I'd be surprised if it reached this tropical hellhole called Brazil within the decade. Heh.
Re:Wiretapping? (Score:2)
This is analogous to someone saying simply 'someone is on the phone on this line'. Does that constitute tapping?
As for the silly us 'wiretapping' laws....
What idiot decided that radio broadcasts on standard modulation were in any way 'private'?
I believe here in the Great Empire of Canada, any cel conversation can be intercepted legally, as there is *no* reasonable expectation of privacy, because it is wireless.
Re:Before you say No Way. (Score:2)
Sure, and if I were to go into the mountains, snow, and other places (which I won't -- nasty, uncomforable things that make you late for dinner...) I'll authorize (Hey, cool, a duck just dropped from the ceiling with a $100 bill in its beak!) tracking. Not otherwise.
/.
This is highly unreliable (Score:4)
And so it begins... (Score:1)
Don't get me wrong, I'm a technofile, it's just the application of the technology that I have a problem with...
I guess if some shmuck locks me in my own trunk, they can trace my call and find me. Then again, if I'm not female, said shumck would just kill me first and save the trouble.
Now, if I could turn this off and on like a transponder, or better yet, have some type of digital connection similar to TCP where my phone can refuse requests from unauthorized trackers, then THAT would be good. Quick, somebody write a standard!
TC
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Damm glad I don't live in Australia right now.
"Laws of Probability"... (Score:1)
( end rant )
This is a really stupid idea (Score:5)
Just to give a sense of how much information is already available online, here's a current incident report from the California Highway Patrol: [ca.gov]
So getting simple traffic data from cell phones is totally unnecessary and inferior to the systems in place.
Cell Phones.. (Score:1)
I think you underestimate this (Score:2)
a) The system in place in LA is partial and expensive.
b) LA is far ahead of most cities, especially relative to the East coast, particularly Philadelphia. The way this cellphone system is described, it could be implimented on the cheap, and without having to mobilize PennDOT (et. al) to get off their asses and do something.
c) A high resolution (per car) system, such as the one described in the article, could be extremely usefull in designing proper freeways. You could get a computer to analyze how each cars interact with one another at particular on and offramps, intersections, etc on a LARGE scale (I don't know of any other system that can claim this). Imagine if you could collect and compile computer data over a period of a month showing that 99% of cars merge left, cutting across traffic, resulting in slowdowns of 20%....you get the point. There are many freeways in Philly, where, for nominal expenses (e.g., traffic light, divider, better lanes, bumping it up a few feet, etc.), they could redesign the traffic flow and alleve traffic concerns considerably, using this type of data.
Re:Hook up to street lights (Score:1)
Re:Here's your "answer" (Score:1)
the original... (Score:1)
sorry, but you're wrong. (Score:3)
GSM cell phones are more than just the GSM voice encoding algorithm. These other security measures include: Gaussian Minimum Shift Keying (GMSK) digital modulation, slow frequency hopping, and Time Division Multiple Access (TDMA) time slot architecture. While i'm aware that they can be broken, it's not nearly as trivial as using a simple modified CB radio scanner. For more information, check out:
http://www.semionoff.com/cellular/hacking/phrea
Re:I stand corrected. (Score:2)
If there's traffic congestion, there will be more people, increasing the likelihood that there's a cellphone in use. Congestion causes delays, making it more likely that cell phones will be in use.
If there are no cell phones to track, chances are good that there's no congestion, which is also useful information.
Re:do the story posters actually read the story? (Score:1)
Rule #1: Never read the story/links on slashdot. Reading the caption alone is enough.
'cos while you're out reading a story all right thinking people are *already* posting their comments. And when you're back *your* posting will be in a third hundred or so and who reads slashdot that far?
So - if you actually read stories your comments will be lost in void.
*SARCASM* Wonderful!! *SARCASM* (Score:2)
Another tool for the Big Brother and his Revenue Collection Gestapo^H^H^H^H^LAW ENFORCEMENT officers to use against us!
I'll just remain out of touch thank you. That way I can actually pay attention to what's going on down the roadway here. And I can avoid all those morons who are cruising at 80mph in their little SUVs and yakking away.
What? Me? Prejudiced against cellular-totin', SUV drivin' fools? DAMN STRAIGHT!
Chas - The one, the only.
THANK GOD!!!
Wrong. (Score:2)
Re:I don't see the big whoop about this. (Score:1)
Query (Score:1)
Swiss (Score:1)
Re:Query (Score:1)
In the US it is usually illegal to walk, skate or bike on a major highway. Definitely on the toll roads. And buses would react to a trafic jam the same as any other vehicle, so I don't see the problem there. For the purpose stated in the article.
Re:Hey, Lisp d00d (Score:2)
Re:Hook up to street lights (Score:1)
Re:I don't see the big whoop about this. (Score:1)
Re:Hey, Lisp d00d (Score:1)
Tracking users (Score:2)
We can't have it both ways, folks; if we want to have the freedom to do whatever we want with any radio transmission we pick up, then we cannot say that the government shouldn't be able to do the same.
If you don't want to be tracked, don't broadcast.
If you want to broadcast, resign yourself to the fact that you can be tracked.
Already being done in 1994. (Score:3)
A pilot project to asses the viability of doing this in Washington DC was underway in 1994.
http://www.itsdocs.fhwa.dot.gov/jpodocs/repts_t
A panel discussion was held at the recent Transportation Research Board meeting in Washington DC (Concurrent session No. 414). Unfortunately notes from panel discussions are seldom published.
http://www.nationalacademies.org/trb/ftp/am/All_S
For those worried about their cars being tracked, I suggest starting at:
http://www.its.dot.gov/
Intelligent Transportation Systems are currently a multi billion dollar area of research. With any luck, in some years time you wont be able to get a speeding ticket, because you wont be driving. It will be too dangerous for humans to drive on the highways of the future - they don't have dependable reactions.
Regards,
-Jeremy
Some "good" applications of this technology (Score:2)
Re:Don't cell phones always send out signals? (Score:1)
In general cellular phones will send a registration message to their closest tower, and will start monitoring the control channel of that tower. Once the signal becomes weak (for example, as you are getting further from one tower), the phone will scan for towers again and will pick the strongest one, and will register again. It will also register just to indicate that it's powered on every now and then anyway. This transmition takes a very small amount of time.
This is mostly true for analog cellular. Digital systems have improved this process to increase battery life and reduce control channel congestion. Depending on the technology, you might see very few registrations after the initial one. I believe GSM won't even register with every new cell it enters, because the provider groups a whole bunch of cells together and the phone needs to register only when it crosses group boundaries. So it sounds to me like this is not sufficient for this use, but what do I know...
"tracking" is nothing new (Score:1)
Well it started with tracking his cell phone when he called a friend. This is nothing new, so if the men in black want to track you, they're already doing it. Get over it, or don't get a cell phone.
A call for vowels! (Score:1)
--
Already Happening in Israel (Score:1)
The companies can pin-point a specific # (the exact resolution of this varies depending on the amount and power of near-by antennaes and on the geographical position of the requested phone), and often do, on the request of the Police/Army (they don't even demand a warren or some sort of court order to do so!).
This can be done whenever your Phone is operating (whether or not you actually talk in it), and was used several times in order to locate and capture criminals (and even a lost solider, recently), but can be easily be misused in malicious ways and is a serious danger to the Right for Privacy of all customers.
Re:Here's your "answer" (Score:1)
Re:How about 4 years old... (Score:1)
Re:Hey, Lisp d00d (Score:2)
If there is actually a good reason for doing this, I'd be happy to do so.
It's coming one way or another, and is old news. (Score:1)
Michael J.
Re:Problem is people yapping on cell while driving (Score:1)
Not entirely true. Some cities have banned the use of cellphones in moving cars (San Francisco area rings a bell to me, for at least one) but IIRC there have been no bans at the state level yet. Colorado has such a bill before the legislature, but I give its odds as being 50-50 at most.
Re:Illegalization (Score:1)
That varies from state to state. In Colorado, for example, a stop may only be made for what's called a 'primary' violation. Adult seat-belt violations are not primaries, meaning that they can only be ticketed if the officer stops the car for some other reason and observes the violation.
OTOH, I believe that child seat belt violations are primaries here. FWIW, I'm given to understand that most of the 50 states are similar to ours.
Re:Wannabee! (Score:1)
>Not really, some PCS/GSM/other digital phones are encrypted, but cellular is no more secure than a CB radio. That's why new(er)scanners have the cellular channels locked out.
Not very well locked out. The Electronic Communications Privacy Act (1989? 1991?) forbade the sale of new scanners capable of intercepting cell frequencies, except to government agencies. However, there are workarounds. Many scanners are designed for police convenience, such that they can be easily modified to remove the cell blocking.
That was a bone thrown to the cell companies. It saved them from having to spend money to go to the (relatively secure) digital, so they could stay analog for a few years longer.
Not those ones... The BLACK helicopters! (Score:1)
But I listen to them on the way to work too.
Ha!
Ha ha ha!
Ha hahaha ha ha!
Seems like the wrong solution! (Score:2)
Besides, all the dicks with the cell phones are the ones driving their bmw's and mercedes' shitty, driving off on the side of the road illegally and thus don't represent actually traffic anyway.
Re:This is highly unreliable (Score:1)
The DC Pilot Project (Score:2)
The 1994 pilot was an analog-only system that used an array of eight antennas feeding eight digital receivers, which in turn fed a whole load of DSP hardware. Once the receiver was tuned, the DSP would do a load of math on the incoming signals and use the phase differences to determine where they were coming from. There were also algorithms to weed out multipath, leaving a single, strong signal to be used in taking a bearing. The goal of the first test was to keep an eye on the DC Beltway from I-270 to Alexandria. To do this, we co-located the DF equipment at eight cell sites around the Beltway. The MTSO (mobile telephone switching office) would give us a feed of calls entering and leaving the cells we covered (each DF site could cover many cells, and some overlapped). Three or four sites were scheduled to get a bearing on the call, and if the phone was located in our area of interest, it was tracked periodically until it left. The resulting location, direction and speed information was then fed back to a Traffic Information Center where a map of the Beltway displayed relative speeds for each segment.
Nothing was actually done with information about the phone itself, but there was a great deal of interest in using a similar system for enhanced 911 services. The project was eventually sold off to Grayson Wireless [grayson.com], who turned it into this product [allentele.com]. There's a description of how it works here [allentele.com]. It's kind of cool to see that a lot of the concepts we built into the prototype seven years ago are still around.
Distribution of cellphones (Score:2)
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Re:Not really (Score:5)
First, the article described 2 systems: One used GPS (and that is the section you quote), and the other used passive reception of the signal. There is no way to turn off the passive system without turning off the phone (not such a bad idea: drive now, talk later). Now, as part of a standard AMPS cell call, the mobile sends out its MIN (mobile identification number). That's the phone number to you and me. It is the actual telephone #, not just a serial #. So, with a commonly available reverse phone book (i.e. a phone book sorted on numbers, not names) you can look up the number and get a name. You can also look up the person you want to track's name, get the phone number (with a regular phone book), and track that person as long as they talk.
What people find so scary about this sort of thing is the fact that it can be abused. And if history is any guide, what can be abused shall be abused. Here in the States we have had various forms of electronic monitoring added to our computer networks, telephone switches, etc. to make it easier (read: trivial) for the various agencies of the various government levels to spy on citizens. If you do not think that the FBI will go to the makers of the passive system and say "You will put in code to allow us to track individual callers.", then you do not know our law enforcement agencies very well.
Re:Here's your "answer" (Score:1)
Re:This is highly unreliable (Score:1)
Why not switch off the phone? (Score:1)
Re:What about the helicopters? (Score:1)
Re:Not really (Score:1)
Um, no.
From my read of the GSM spec (a friend bought me the huge expensave book for Christmas one year...) the update timer is way shorter then hours.
More importantly from putting my 1900Mhz-GSMish phone near my computer speakers I heard transmit bursts from it multiple times an hour. Also just after it was turned off (as in I press off, the backlight turns on, it says "powering down", screen goes blank and THEN "blip-blip-blip").
Beats me how ofen CDMA phones transmit (I know they do handset assisted cell handoff, so they will transmit quite a bit when they are close to a cell boundry). I havn't read the spec, and I havn't noticed any interference from the phone yet (I switched when the provider in my areaa ditched GSM@1900Mhz to go with CDMA@1900Mhz, which has been providing me with fewer services, but doing them just as well, for moer money, what a bargin!)
Re:Here's your "answer" (Score:1)
Illegalization (Score:3)
Dan
What about the helicopters? (Score:2)
How entirely accurate could this be? This based on the errant assumption that all the traffic on the highways consists of yuppie puppies yacking away while driving (which is illegal in many urban areas--cell phoning while driving...not yuppies)...
Why not just stick with the good ole' traffic copters?
--snake
Hook up to street lights (Score:1)
No more sitting at a red light watching noone go through.
~Chris
accident prediction (Score:4)
Conventional wisdom states that cell-phone users get into more accidents and have less control over their speed; I wonder how this will affect the data.
-AC
Re:Hook up to street lights (Score:1)
Poor idea... (Score:1)
Re:Problem is people yapping on cell while driving (Score:1)
Re:What about the helicopters? (Score:1)
Re:What about the helicopters? (Score:1)
Using the drivers themselves is a lot cheaper: no helicopter maintence, pilots, insurance, etc. And it works well in bad weather (though if you're blabbering away on a cell phone during a snowstorm, maybe you shouldn't be driving). It is also more accurate: why not get traffic data from the people on the road? It makes sense.
Of course, it all depends on enough cell phone usage. If no one's talking, there won't be any info.
As far as yuppies are concerned, we could track them with radio collars to learn their ancient migration patterns to the local Starbucks.
~~~~~~~~~
auntfloyd
Only when the phone is completly active? (Score:1)
Re:Monitoring (Score:1)
Anyway just a few thoughts
Alex
Re:What illegalization? (Score:1)
It's fine by me. The fewer things preventing the a$$hole going 20Km/h _below_ the speed limit in the fast lane (which, as we all know, is for going 20Km/h _over_ the limit) from realizing that he's holding up traffic, the better...
Re:Wiretapping? (Score:1)
This is a really smart idea (Score:2)
Now consider the alternative offered by RadioCamera:
a relatively small number of units cover a large ares. Furthermore, they are installed in existing cell sites that have all the necessary infrastructure. These systems can easily be afforded by places that are not as well off as California.
I would expect that slashdot readers should know by now that silicon is cheaper than infrastructure.
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Here's a link to the company site (Score:2)
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In the UK... (Score:1)
Point is that if you work out how much data is stored (assuming that they don't bother with keeping photographs of the cars unless they have been speeding) then there is very little and they could easily keep records of where all cars travelling over a reasonable period in a certain region go.
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To hell with you, I never liked you, you are no friend of mine...
Re:I hear you but (Score:1)
Re:I don't see the big whoop about this. (Score:1)
But those days are gone, due to extra bandwidth, and now there is only the simpler StarTribune's map.
Discussion (Score:1)
Obviously there could be benefits. Using it for law enforcement and searching for missing people to name two. But that may be as far as it can go, without upsetting people. However, in my opinion, there would have to be strict laws to govern this technology. As we've seen with other technologies in the past, if put into the wrong hands it can be misused and abused.
I believe the topic needs to be extensively debated, both publically and in government circles, before it can become a tool we can all use.
Re:This is a really smart idea (Score:1)
Re:Here's your "answer" (Score:1)
itachi
Re:Poor idea... (Score:1)
Edward Burr
Hey, Lisp d00d (Score:1)
((lambda (x z) (format "~a~a")) "lisp" "d00d")
And how, pray tell, will the format form obtain its parameters? That's right. It won't, because you haven't bothered to actually pass them to format. As long as you're showing off your Lisp wizardliness, you probably want to use a closure instead, as in the much more idiomatic:
(let* ((x "lisp")
(z "d00d")
(pr (lambda () (begin (display x) (display z) (new-line)))))
(pr))
Re:I hear you but (Score:1)
For the non-US crowd out there, 911 is a phone number you can dial to get emergency help. It's normally used for medical, fire, and crime related problems.
I can see the use for this technology (it's pretty obvious). I thought it was great when 911 got the ability to know where the caller was without relying on a panic stricken victim or victim's friend to give directions.
However, it's just kind of creepy to know that I can be tracked so easily. Okay, right now it doesn't invade privacy but how long will that last?
Re:Here's your "answer" (Score:2)
Re:Here's your "answer" (Score:2)
Well lets get carried away instead... (Score:3)
For privacy: any car entering an area is assigned a call sign, and when it exits that broadcast area its ID is handed-off to a new car coming in... *shrug* would make more sense then cell phones.
#include <signal.h> \ #include <stdlib.h> \ int main(void){signal(ABRT,SIGIGN);while(1){abort(-1)
Re:Here's your "answer" (Score:2)
I really hate this sort of thing... (Score:2)
But along with that comes the potential for abuse. And that abuse will happen, given enough time. Or at least, someone will certainly try to abuse it.
Right now, though, tracking people via cellphone isn't very practical. Each phone has a fingerprint, but you have to map fingerprints to individuals before you can track specific people, and I don't believe anyone has records of that sort (perhaps the phone company, but I'm not sure if they do). Without those records, you need to find the cellphone itself, which means finding the user, which renders the whole tracking pointless because you've already found the target.
Now, if our pals in the government were to require cellphone registration with the Feds, that's another matter entirely. I wonder when someone's going to try and get that bill passed...
Don't cell phones always send out signals? (Score:2)