trips file keeps getting larger?

[scrayne]

With every GTFS release, it appears that the "trips" file gets larger
-- making it more difficult to import the data into a SQLite
database. I can't figure out why the file should be getting larger.
Does anyone have an explanation?

Susan

[Sunny]

Could this be because of the way the trips are split up? There are
separate sets of trips for each of these time periods, and trips that
run on more than one of these must be listed multiple times.

-Monday-Thursday
-Friday
-Saturday
-Sunday
-Day before MLK Day
-MLK Day
-Day before President's Day
-Monday-Thursday with schools closed
-Friday with schools closed

Can this list be consolidated into weekday, Friday only, Sat, Sun,
holiday, and school open extra? That way the trips.txt can shrink.

For example, there are 8 S84 trips listed in the public schedule, but
there are 40 entries in trips.txt. And the S84 doesn't even operate on
weekends and holidays.

[Frumin, Michael]

Note: this email reflects my imperfect understanding as a very tightly integrated client of our bus schedule/network data.

In theory, the weekday school-open trips could be lumped into a separate service ID that is layered on top of the weekday school-closed service as needed. In practice it's of course not that simple, for reasons including the following:

1. The difference is not purely additive in all cases. Sometimes there are minor changes/adjustments to the baseline school-closed service.

2. We generate 2 entirely different sets of schedule files, for a number of reasons including the above, and also: even when all the trips are the same, the optimization programs that generate schedules block the trips differently depending on what school service is to be made.

Thus, even if it were possible, it would be very burdensome to 'diff' the 2 sets of files to create the service ID's as suggested.

As for why we have Friday different from Mon-Thursday, and why we have a Sunday schedule for normal Sundays as compared to the Sunday before a holiday, etc., has nobody ever explained that on this list? If not, I can take a stab at it.

Thanks,
Mike

[John Paul N.]

Mike and everyone else,

I think a reason that was explained to me before (it might have been
Mike, even), is that differences arise with trips on or around
midnight or some other time frame, and also that the GTFS does not
support negative time values. I think another recent thread addresses
this, better than I ever could.

If someone fishes out that long thread I created once upon a time, I
still believe the theory about re-engineering the calendar between
regular and "special" trips I laid out there is correct. But as I said
then, and I will say again now, it is the MTA's job to provide
accurate data, and that must be respected. If, through refactoring, an
error is introduced in the smaller file, the MTA is on the hook for
that, and that is something no one wants here. I will surmise,
however, that schedules for days like MLK Day, Presidents' Day, Day
after Thanksgiving, etc. are sufficiently different from regular
schedules that I would not attempt to shoehorn those days into the
regular schedule.

Now, I am aware that the OneBusAway GTFS transformer has an option
called CalendarSimplicationStrategy. It sounds like it can apply here,
but I admit I do not understand how to use it. If Brian can weigh in
here, that would be great.

Thanks,
John Paul R. Nazarrea