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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.
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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.