Slashdot Mirror
Cell phones used to track traffic
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"?
Does that mean that a dead-halt traffic jam will look exactly the same as a responsible driver pulling over to use the phone?
They're making a very error-prone assumption that cell phones are distributed uniformly, or at least approximately uniformly, throughout the Bay Area. I will guarantee you that a jam in downtown of San Jose will be reported even if there's a slight slowdown, and a jam around some less well-off areas (e.g. south SF) is quite likely to go completely unnoticed. And it appears more or less impossible to make adjustments for this; so what data comes out of this system should be double checked at the very least.
// zyqqh
Just to give a sense of how much information is already available online, here's a current incident report from the California Highway Patrol:
So getting simple traffic data from cell phones is totally unnecessary and inferior to the systems in place.
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.
www.eFax.com are spammers
I want to be the guy in the control booth who sees the two 95 mph dots heading towards each other, see them meet, see the dots dissappear, and see them appear again at 0 mph as each calls his/her lawyer.
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