Re: RLC triggering on legal right on red

"gpsman" <gpsman@xxxxxxxxxxxxxxx> wrote in message news:75114c8c-9e5f-45b7-884b-9479be435cf4@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
On Jan 15, 9:27 am, "Daniel W. Rouse Jr."
<dwrous...@xxxxxxxxxxxxxxxxx> wrote:
"gpsman" <gps...@xxxxxxxxxxxxxxx> wrote

* Except that if a RLC camera flash is occurring for any reason other than
to indicate a red light camera violation occurred for specifically running a
red light,

And if it flashes to compensate for exposure...?

* If you're talking about a pre-flash? Then it should still only be occurring on red a fraction of second before the main flash. Flashing on green is at least 3.5 seconds too early--even more earlier the longer the light remains green--assuming an almost immediate change from green to yellow, a 3 second yellow time interval and an 0.5 second grace period before the camera takes the photo. Furthermore, digital cameras tend to use other factors for exposure compensation, not just the pre-flash.

What do you propose the flash intended to "indicate", to whom, and
why...?

* The flash has indicated a vehicle has crossed the limit line while the light was NOT red, right?

the camera is malfunctioning

You don't know that. What you know about the operation of RLCs is
dwarfed by what you don't know.

* If it's flashing for any other reason that a driver crossing the limit line by running the red light, it is clearly a malfunction. If the designer of the system intended it to flash for any other reason, it should not be called a red light camera and the public should be informed that those cameras are continuous monitoring, subject to taking pictures at any time even if the light is not red.

and is a de-facto traffic hazard of
its own.

Did you see anything in Brent's vid that suggests those drivers
considered it a hazard...?

* Doesn't matter, it's a distraction in my own opinion, and therefore a potential hazard. Drivers have cause to wonder why the camera flashed when they didn't run the red, it will distract from otherwise focusing on defensive driving.

Do they flash apparently without cause for other reasons?

I don't know, maybe they were capturing random traffic for
monitoring/surveillance purposes?

There ya go, Sparky. Lather. Rinse. Repeat.

You don't know.

* It would make sense to record traffic during a period of time, for example, in the event of a stolen vehicle just recently reported. Analyze the photos to see if the stolen vehicle was seen in the area/captured by the cameras. Yeah, okay I don't know that but it's still a reasonable enough guess.

Still, a RLC should only flash when a
photo has been taken specifically for actually running a red light. If the
driver stops on red and then makes a right turn (or, for a one-way street it
can be a left turn) on red, the RLC must not ever flash.

Why...?!

* Because it is a Red Light Camera? Only supposed to record running red light violations? Stopping before turning is not running the red light as long as the stop occurs behind the limit line, and the sensor can record a vehicle at 0mph for the minimum required time (let's assume a minimum of an 0.5 second stop).

No bugs or any other design issues
should ever be tolerated, the RLC camera technology does need to be 100%
error free if the photo tickets are to be enforced properly.

Right. RLCs must be perfect. It's only fair that they adhere to the
identical standard demanded of you, whenever you do whatever it is you
do...

* Programs, however, can and often due have bugs. At the highest level of abstraction, the red light camera is effectively a device running some software and/or firmware that makes the determination that the sensor has been tripped and a violation photo should be taken, correct?

Here's a reasonable general expected use case for a red light camera:

1. Light turns red.
2. Grace period before the camera takes the photo elapses.
3. Camera takes the photo of any vehicle crossing sensor past the limit line while the light is red.

Here's an easy defect scenario, as an example, from the use case above and the initial topic of this discussion.

Steps to reproduce:
1. Light is green
2. Cross the limit line at the normal speed of traffic flow

Observed behavior:
The red light camera flashes for each vehicle crossing the limit line while the light is green, rather than red.

Expected behavior:
1. The red light camera should only be flashing when a vehicle crosses the limit line while the light is red.
2. The red light camera should not flash for a vehicle that has stopped before the limit line, before making a right turn on red in the absence of signs prohibiting right on red.

[snip...]

.

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