On 11/25/11 12:02 , Jay Hennigan wrote:
> On 11/25/11 11:34 AM, Joel jaeggli wrote:
>
>> Cars generically cause at lot more deaths than faulty traffic
>> controllers 13.2 per 100,000 population in the US annually.
>
> The cars don't (often) cause them. The drivers do. Yes, there are the
> rare
On 11/25/11 11:34 AM, Joel jaeggli wrote:
> Cars generically cause at lot more deaths than faulty traffic
> controllers 13.2 per 100,000 population in the US annually.
The cars don't (often) cause them. The drivers do. Yes, there are the
rare mechanical failures but the most likely cause is wet
On 11/22/11 08:16 , Jay Ashworth wrote:
> - Original Message -
>> From: "Owen DeLong"
>
>> As in all cases, additional flexibility results in additional ability
>> to make mistakes. Simple mechanical lockouts do not scale to the
>> modern world. The benefits of these additional capabiliti
I have to jump in on this thread. Traffic light controllers are a fun category
of technical artifacts. The weatherproof boxes that the relays used to live in
have stayed the same size for decades, but now the controllers just take a
teeny tiny circuit board rattling around in this comparativel
On Wed, Nov 23, 2011 at 05:45:08PM -0500, Jay Ashworth wrote:
>
> Yeah. But at least that's stuff you have a hope of managing. "Firmware
> underwent bit rot" is simply not visible -- unless there's, say, signature
> tracing through the main controller.
I can't speak to traffic light controller
On 11/23/11 3:38 PM, Jay Ashworth wrote:
> Yes: but as Don Norman would ask: *where was the failure here*? You can't
> blame all of it on the field tech, even though he had the Last Clear Chance
> to avoid it, if the rest of the system wasn't designed to help protect him
> (procedures, labeling,
Original Message -
> From: "Jay Hennigan"
> A somewhat inexperienced technician arrived on scene rebooted the
> controller and it went back to factory defaults which are N/S vs. E/W.
> Had the conflict monitor (a circuit board with a diode array, hardware -
> not software) been correctly
On 11/23/11 2:52 PM, Jay Ashworth wrote:
> Well, sure: what's the *incidence* of conflicting greens?
>
> I wasn't suggesting that the incidence of accidents would be any different
> between conflicting greens and other types of failures (though my intuition
> is that it would be higher), but that
- Original Message -
> From: "Owen DeLong"
> >> but that's not the only risk. When the traffic
> >> signal is failing, even if it's failing with dark or red in every
> >> direction, the intersection becomes more dangerous. Not as
> >> dangerous as conflicting greens,
>
> Within each intersection controller is a PC board with a diode matrix
> called a "conflict monitor". It has inputs from all of the green and
> yellow phases including pedestrian walk signals, turn arrows, etc.
>
> It's the job of the traffic engineer installing the system to program
> the confli
Mark Radabaugh writes:
> On 11/23/11 11:23 AM, valdis.kletni...@vt.edu wrote:
>> On Wed, 23 Nov 2011 11:14:34 EST, Bryan Fields said:
>>> So really all a hacker needs is a pair of dykes, some electrical tape, and
>>> an
>>> all black jumpsuit.
>> Actually, you want a really dark blue jumpsuit.
On 11/23/11 11:23 AM, valdis.kletni...@vt.edu wrote:
On Wed, 23 Nov 2011 11:14:34 EST, Bryan Fields said:
So really all a hacker needs is a pair of dykes, some electrical tape, and an
all black jumpsuit.
Actually, you want a really dark blue jumpsuit. All-black creates a sillouette
in
all but
On Wed, 23 Nov 2011 11:14:34 EST, Bryan Fields said:
> So really all a hacker needs is a pair of dykes, some electrical tape, and an
> all black jumpsuit.
Actually, you want a really dark blue jumpsuit. All-black creates a sillouette
in
all but the very darkest conditions.
pgprHPVYAjpnH.pgp
De
On 11/22/2011 23:29, Jay Hennigan wrote:
> But, an external cracker even with full access won't be able to cause a
> conflict. Massive traffic jams by messing with the timing, short or
> long cycles, etc. but not a conflict.
So really all a hacker needs is a pair of dykes, some electrical tape, a
On 11/22/11 8:16 AM, Jay Ashworth wrote:
> - Original Message -
>> From: "Owen DeLong"
>
>> As in all cases, additional flexibility results in additional ability
>> to make mistakes. Simple mechanical lockouts do not scale to the
>> modern world. The benefits of these additional capabilit
>
>> but that's not the only risk. When the traffic
>> signal is failing, even if it's failing with dark or red in every
>> direction, the intersection becomes more dangerous. Not as dangerous
>> as conflicting greens,
>
> By 2 or 3 orders of magnitude, usually; the second th
On Tue, Nov 22, 2011 at 02:26:34PM -0500, Jay Ashworth wrote:
>
> Yes, but the complexity of a computerized controller is 3-6 orders of
> magnitude higher, *and none of it is visible*
You can't see the electrons in the relays either.
> > Some other things to consider.
> >
> > Relays are more li
> Relay logic has the potential for programming (i.e. wiring) errors
> also.
Yes, but the complexity of a computerized controller is 3-6 orders of
magnitude higher, *and none of it is visible*
> It's not fair to compare "conflict monitor" to "properly programmed
> relay logic". We either have to
On Tue, Nov 22, 2011 at 11:16:54AM -0500, Jay Ashworth wrote:
> - Original Message -
> > From: "Owen DeLong"
>
> > As in all cases, additional flexibility results in additional
> > ability to make mistakes. Simple mechanical lockouts do not scale
> > to the modern world. The benefits of
- Original Message -
> From: "Owen DeLong"
> As in all cases, additional flexibility results in additional ability
> to make mistakes. Simple mechanical lockouts do not scale to the
> modern world. The benefits of these additional capabilities far
> outweigh the perceived risks of program
20 matches
Mail list logo
