How to check "Signal Cycle Start Time" of a perticular trip?

[Mallikarjuna]

Hello Mr. Greg,

I have another question. I have a bunch of trip logs recorded in the field. Since the timing plans change during the day, I have synchronized the clock when there is change in timing plan. So, I want to check the Signal Cycle Start Time for a particular trip log which is synchronized to a correctly timed intersection so that my colleague can use this Signal Cycle Start Time for her trip logs to make them appear correct on the diagram, because her trips were synchronized to an intersection that has incorrect signal timings.

I can use Time Shift on Diagram option, but she want to use the same Signal Start Time what I have got. I want to know the difference between those options. Because they appear to function in a same way.

Finally, when we have option to override recorded signal cycle start time in trip log properties window, why does that show different date and time for that particular trip log? I think it should have shown the recorded Signal Cycle Start Time for that Trip Log.

Thank you. Looking forward to your reply.

- Arjun

[bullock]

Hi, Arjun.

That's a good suggestion, to display somewhere (in the Trip Log Properties) the Trip Log's recorded Signal Cycle Start Time. Thank you. I'll add that to an upcoming version.

If you and your colleague are using the same *.Dgm file, then she can set the Signal Cycle Start Time for her Trip Logs by selecting them in the GPS View (using the Shift or Ctrl keys to highlight all of them), then right-clicking on the selection and choosing Signal Cycle Start Time: <the applicable timing plan>.

If that's not an option, then at present, you can view the recorded Signal Cycle Start Time only if the clocks in the *.Dgm file are still synched as they were when you recorded the trip log -- that is, provided the clocks have not been resynched since recording the trip log. If that's still the case, then you may see that trip log's Signal Cycle Start Time in GPS View: Clocks after switching to the appropriate timing plan. Indeed, that will still show the Signal Cycle Start Time of all trip logs that have been recorded since that date/time.

You're correct that the Time Shift on Diagram and the Signal Cycle Start Time have the same purpose in regards to an individual trip log. The difference between the two is that the Time Shift on Diagram is essentially advertised (by its name) to be an artificial offset introduced for display purposes, whereas the Signal Cycle Start Time is essentially advertised to reflect the results of the user's having either

• entered the Signal Cycle Start Time in GPS View: Clocks prior to recording the trip log, or
• performed the clock synchronization step prior to recording the trip log.

Think of it as a way of documenting your confidence in the trip log's offset on the arterial timings diagram. When I see a trip log with a nonzero Time Shift on Diagram, I know that I (or some other user) adjusted the offset artificially. Otherwise, if the clocks were synched and the signal timings are correct, I'm confident that the trip log trajectory is shown at its actual offset within the cycle.

Finally, when we have option to override recorded signal cycle start time in trip log properties window, why does that show different date and time for that particular trip log? I think it should have shown the recorded Signal Cycle Start Time for that Trip Log.

I agree with you (provided the clocks were synchronized when the trip log was recorded). I'll change that as well. Thank you for pointing that out. In the cases where the clocks weren't yet synchronized before recording the trip log, I'll continue to just initialize it to "now". Please note, however, that even after making this change, the value displayed here will not, in general, be a reliable indicator of the Trip Log's recorded Signal Cycle Start Time. That is, if someone has previously overridden the Trip Log's recorded Signal Cycle Start Time, then that overriding value will be the one displayed instead of the recorded value.

Regards.
Greg

[Mallikarjuna]

Thank you Greg,

I think that change will be very helpful in trip log properties window, so that we will have an idea on when the particular trip was synchronized. Because we got some trip logs which are perfectly synchronized with signal clock, but some are not. So we wanted to know the Signal Cycle Start Time of those trips.

Your suggestion to view Signal Cycle Start Time by choosing applicable timing plan is good. But I don't know weather the timing plan was selected when we synchronized it. I think it remembers Signal Cycle Start time for that particular timing plan only if it is selected during the time of synchronization. Otherwise, it will overwrite Signal Cycle Start time of whatever the timing plan which is selected. We did not plan properly before we synchronize as we thought that the trip logs are going to be fine even if we add new timing plans. So, I really we can rely on this option all the time.

Thank you
-Arjun

[bullock]

Hi, Arjun.

If you know now which timing plan was active in the controllers at the time the trip log was recorded, and if either

• that timing plan has already been synched in Tru-Traffic TS/PP (that is, you've already set the Signal Cycle Start Time for that timing plan), or
• you can now set the Signal Cycle Start Time for that timing plan -- even if it's a time after the date of the trip log,

then it's not too late to correct that trip log using the procedure I outlined above: Right-click on it in the GPS View and choose Signal Cycle Start Time: <the applicable timing plan>.

Note that the order in which these various events occur is not critical:

1. The trip log is recorded,
2. The Signal Cycle Start Time is set for a given timing plan, and
3. The Trip Log's recorded Signal Cycle Start Time is overriden.

These events can occur in any order, and moreover, the Signal Cycle Start Time assigned to the Trip Log may post-date the Trip Log itself.

If you know the Signal Cycle Start Time in the controllers (often it's midnight) for a given timing plan, then you can just hand enter it into that timing plan for any particular date, then assign it to the applicable trip logs.

Regards.
Greg

[bullock]

Version 8.0.0.18, now available for download, has a few improvements to simplify overriding the Signal Cycle Start Time.

Thanks again for the great suggestions.

Regards.
Greg