Red Light Camera

[RichLockyer]

Originally Posted by CTRider

The rated speed was 55. The intersection in question had a 2 second yellow while the rest of the lights down the line had 5 sconds. The left turn arrow had a 1.5 yellow and only a 7 second green.

I seem to think it was 20/20 on ABC, so you can't blame NBC's Dateline for fudging things.

I don't have any more faith in ABC than NBC.

At that size intersection, 4.5 to 5 seconds would indeed be within standards, but like I said... on a modern solid state controller (and any controller made since 1980), it is impossible to program less than 3 seconds of yellow. The controller software will not accept the entry.
The old electro-mechanical units designed in the 1930s? Sure... you can adjust the pins to do anything you'd like.

The short green time is another story. A typical minimum green will be anywhere from 2 to 4 seconds. Max green will be dictated by the coordination cycle time. With a 55mph limit and 8 lanes, there is going to be a lot of time needed out of that cycle for the through movements, so the engineer has two options.... run a longer cycle time, which increases delays for people on the side street, or take the time away from the left turns and the side streets. 7-10 seconds is a very common max green for a low-volume left turn.
If only one or two cars are present, the controller will only time the minimum green. Additional cars in the queue will trigger extension time that will hold the green until the timer reaches the max green.

If the signal was timing 7 seconds on that left turn no matter how many vehicles were waiting, then it's possible that it was an electromechanical unit with no vehicle detection system.

[mrblanche]

OK, here's an organization you can trust.

Six cities fined for shortening yellow lights for profit

[RichLockyer]

Originally Posted by mrblanche

OK, here's an organization you can trust.

Six cities fined for shortening yellow lights for profit

I didn't say they weren't shortening yellow times. I know for a fact that they do (or did, the "busts" cited in that article were responsible for thousands of tickets being thrown out and courts ordering engineers to restore timing).

My point was that the 2-seconds stated by the ABC team is not a possibility on solid-state controllers.

Only in the Nashville case is the claim made that the yellow time is shorter than 3 seconds. In the other cases it is above 3 but less than recommended timing, or not stated but less than recommended.

[CTRider]

Originally Posted by RichLockyer

I don't have any more faith in ABC than NBC.

At that size intersection, 4.5 to 5 seconds would indeed be within standards, but like I said... on a modern solid state controller (and any controller made since 1980), it is impossible to program less than 3 seconds of yellow. The controller software will not accept the entry.
The old electro-mechanical units designed in the 1930s? Sure... you can adjust the pins to do anything you'd like.

They didn't say what the system was. I only know what I saw.

The short green time is another story. A typical minimum green will be anywhere from 2 to 4 seconds. Max green will be dictated by the coordination cycle time. With a 55mph limit and 8 lanes, there is going to be a lot of time needed out of that cycle for the through movements, so the engineer has two options.... run a longer cycle time, which increases delays for people on the side street, or take the time away from the left turns and the side streets. 7-10 seconds is a very common max green for a low-volume left turn.

I've seen very short green arrows at very high volume intersections - with no chance to turn during the cycle since the "yeild" mode is disappearing from many intersections (which I feel only encourages people to run a red arrow).

One intersection near me has a 4 second green arrow where 18 wheelers headed toward a distribution facility often turn. A single truck can't even complete the turn in the time the light is green, much less allow anyone else to get through it behind them.

If only one or two cars are present, the controller will only time the minimum green. Additional cars in the queue will trigger extension time that will hold the green until the timer reaches the max green.

If the signal was timing 7 seconds on that left turn no matter how many vehicles were waiting, then it's possible that it was an electromechanical unit with no vehicle detection system.

That's the problem. I encounter many intersections (even rebuilt ones with new hardware) that, while the use a tripper to detect a car, they are purely timer based to set the time that the light stays green. Likewise, there is an intersection near me with new LED lights that will trigger green arrows whether someone is looking to turn left or not.

On the other hand, a rather busy intersection near it where turning left without an arrow is very difficult has a short green arrow and the tripper refuses to detect motorcycles. While a yield green is provided, actually using it is unlikely since oncoming traffic is pretty steady there due to the volume on a narrow section of road (the intersection is just up the road from where two lanes combine into one).

[tai42]

Originally Posted by RichLockyer

My point was that the 2-seconds stated by the ABC team is not a possibility on solid-state controllers.

Sure it is. Maybe not through the standard settings for the unit, however I bet the unit can be modified either by changing the software in the microcontroller or FPGA, or adding some additional circuitry to bypass it. Of course, making such a modification would show intent to drive up the number of violations and whoever did it should be prosecuted.

[CTRider]

Originally Posted by tai42

Sure it is. Maybe not through the standard settings for the unit, however I bet the unit can be modified either by changing the software in the microcontroller or FPGA, or adding some additional circuitry to bypass it. Of course, making such a modification would show intent to drive up the number of violations and whoever did it should be prosecuted.

I'm pretty sure that reducing the yellow light time on only camera equipped intersections also shows intent to drive up violations, too.

..and by the way, I agree. If you can flash a chip, you can reflash it with new data.

[RichLockyer]

Originally Posted by tai42

Sure it is. Maybe not through the standard settings for the unit, however I bet the unit can be modified either by changing the software in the microcontroller or FPGA, or adding some additional circuitry to bypass it. Of course, making such a modification would show intent to drive up the number of violations and whoever did it should be prosecuted.

Not by the traffic engineer or a field tech, and due to liability exposure, none of the 6 or 7 companies that write the software would agree to do it.

On controllers that have their software hard-coded on PROM, there's no way to do it without burning a new PROM, and the manufacturers did not release their source code, so it would require someone able to decompile the code. The other problem is that the PROM chips for those controllers are no longer available.
You're REALLY giving traffic engineers too much credit. I know of only a handful that would be capable of even knowing what would need to be done, and maybe a dozen techs in California capable of actually doing it.
Most of the field "techs" are little more than housekeepers. They can read a timing sheet and verify that the controller programming matches it, they can verify that the detection is operational, that nothing smells burned, and they can vacuum out a cabinet, and change the air filter and any burned out light bulbs.
Maybe half are halfway decent at troubleshooting a wiring problem in the conduits. Most of them didn't even know how to operate a computer 5 years ago.... many still don't.

Prior to that, controllers were programmed via pins. The pins were bit mapped so, in the case of the yellow or extension time, the first pin was .5 second, the next was 1, the next was 2, and the next was 4. You could pin all of them for a 10.5 second yellow, but removing all pins set it to 3.
Minimum and maximum green and pedestrian timing eliminated the fractional second and started at either 1 or 2 and mapped up from there to 16 or 32 (allowing a maximum green time of 62 seconds).

The traffic engineer would have to request that the controller be modified, and from what I recall of how the old 901 and 911 controllers were built (been about 15 years since I've worked on one), I'm still not sure that it was possible.

What IS possible is for a failure in the power supply to screw up the clock pulses and result in the controller timing either double or half time, but that would impact all timing, including the coordination, and would be quickly repaired by the maintenance department.

[Hot Cruiser]

Originally Posted by CTRider

It would have to be Europe. Look at the caption where it says "Foto". That indicates Germany.

As far as the rest, no that's not a cigarette - that's her thumb. She's using a perfect 10 and 2 position, but her mind is resting somewhere in between: at lunch.

I don't know about "Foto" necessarily indicating that it took place in Germany. I lived and traveled in Europe and "Foto" is used in various countries, even in Russia when the signs used Roman letters.

[Jonathan70363]

Originally Posted by Gpz1100

This says it all...

Hey, when you're going to Country Buffet you have to get there NOW mister.

[tai42]

Originally Posted by RichLockyer

You're REALLY giving traffic engineers too much credit.

Well, I know at least one guy who might be able to. (I think I'm still getting stopped at every light in the valley because of pointing out a few physics errors he made!)
But my point was that it's not impossible. Just like gas pumps aren't supposed to be modified to say you've got more gas than actually pumped, but it's been done. And similarly, anyone undertaking such modifications would be doing so with intent to generate more ticket revenue.

[sharky1381]

Rich is the expert in signal maintenance so I will leave the technical aspects of this discussion in his capable hands. I will try to address some of the procedural and other issues with the knowledge I have obtained doing considerable research into red light photo enforcement programs while working on my Master of Science in Emergency Services Administration in 2006 and supervising the Photo Enforcement Unit of my department for some time. With the rapid expansion of the number of red light camera systems throughout the U.S.A. there have been a number of mistakes and misconceptions about these systems as well as some poorly thought out and implemented programs. Most of the cases involving the poorly managed programs occurred when red light cameras were just starting to be installed and there was not any case law or written regulations for their use. A case in point is the city of San Diego which entered into a contract that gave the company operating the system a percentage of the income from fines. There was little PD oversight and as a result there was impropriety regarding the signal interval timing. Thousands of citations were invalidated and case law introduced that precludes contracts that allow payment based on a percentage of fines. It was also ruled that a sworn police officer must review every violation and approve the issuance of any citations thus taking that responsibility out of the hands of the contractor.

The issue of increased rear end collisions is always brought up by opponents and immediately following installation a small increase in such minor collisions is normal. However, this spike is short lived and once people get used to the system being in place such collisions return to the level prior to installation or may even be reduced since people tend to be a little more alert when they know photo enforcement is in place. On the other hand, the occurrence of much more serious, high speed broadside collisions such as those caused by red light runners, are reduced immediately. This is particularly true when the proper criteria are used in choosing intersections to be equipped with red light cameras. Intersections should be chosen based on collision rates and the rate of red light violations. The systems are set up so that clear photos of front and rear plates as well as the driver are taken. There is also a video that clearly shows the sequencing of the light and the position of the vehicle in reference to the limit line. There is a digital clock running in the video that shows how long the light has been red when the car goes through and also shows the speed of the violator’s car.

The digital image is reviewed by an employee of the company that installs and maintains the equipment and if it is their opinion that an offense occurred it is forwarded to the P.D. An officer reviews the video and compares the license photo of the registered owner to the driver in the video. If a positive I.D. is not made a letter goes out to the R.O. asking them to identify the driver. If they can’t or fail to respond then the license photos of all residents of the R.O. address can be compared. Otherwise no cite is issued. Ultimately it is a sworn officer who has to determine if what is shown on the video constitutes a citable offense and if a positive identification can be made of the driver. If so a citation is sent in the mail and the person cited has the opportunity to review the video and fight the citation in court. A few years ago the Grand Jury of Orange County, California did an investigation of photo enforcement programs and determined that while some jurisdictions have a positive income, on average the programs tend to be revenue neutral since just as many agencies lose money. That is the way it should be since the idea is to provide increased safety at problem intersections, not provide income.