TriMet's busiest MAX stations (plus daily on off stats for all others)

[eph]

TriMet's busiest MAX stations
Portland's 10 busiest MAX stations, in combined ons and offs per stop daily, are (as of fall 2010):

...

"However, if all four Pioneer Courthouse Square MAX stops and all four Rose Quarter stops were counted together, Pioneer Courthouse Square would be TriMet's busiest with 21,827 ons or offs, followed by Gateway with 14,852, then Rose Quarter with 13,647."

There are stats for every station too:
http://portlandafoot.org/w/MAX#TriMet.27s_busiest_MAX_stations

So 21,827 "ons or offs" per weekday is the maximum. Then I figured (based on MAX (LRT) schedules) the peak hours (where service period is less than 10 minutes) I get 3 hours total rush-hours. Then I got the ratio of rush-hour rides to weekday rides from the link below and got 42% (this is probably high) so based on this, I get a peak station boardings of 3,056 for all 4 directions. This number is high because some transfers will simply see Podcars drive straight through.


http://trimet.org/news/releases/oct13-september-ridership.htm


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[eph]

Percentage should be rush-hour rides divided by total weekday rides which is 30%, not 42%.
That bring the per hour station ons and offs to 2,183 per hour for all four directions.


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[eph]

Nov. 2010 data from TriMet site: "Weekday ridership averaged 62,800 on the Blue line, 22,700 on the Red line, 15,900 on the Yellow line, and 21,700 on the Green line"

So about 65,000 weekday boardings on the busiest (by far) line.  Assuming they all pass the same point, we have 65,000*0.3 rush-hour factor/(3 hours of rush-hour * 2 directions) = 3,250 pph per direction at peak hours.  At 2 second headways, 2 Podcar lines would be needed, 3 lines if 3 second headways are still warranted in the future.

It should be possible to add up station boardings and applying the same ratio to determine at which point along the line a second (or third) line is needed so that a total guideway length can be determined.  This assumes multiple lines are needed using today's ULTra Podars for example.

The 3 other lines are already below existing Podcar capacity.


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[Eric Johnson]

Your assuming ALL passengers go through this core area which I feel is unlikely. http://trimet.org/maps/railsystem.htm Many could catch LRT at the end or part way out and get off before they get to the square area thus reducing the needed capacity in this area. At the same time, LRT has four lines sharing 2 sets of track so a PRT system could have a 4 lines wide by 4 lines deep network covering this area to 1.5 miles square or 3x3 miles. Worst case you add to the core grid area for 3 miles or so to get around the bump in traffic.

EricAZ

http://trimet.org/maps/railsystem.htm

[eph]

Right.  True on the worst case assumption.  That was the point given lack of data.

I haven't been able to find the distance between stations to figure out exactly how much of the centre core needs to be a grid or multiple lines.  This info is needed to determine how much guideway is needed based on the ULTra numbers.


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[Eric Johnson]

The Portland core area is roughly 1.5 miles squared as its bounded by a river on the east and a ridge line on the west with a 1/2 sq mile grid that's 12 miles of guideway with say 24 stations in a 4 sq mile area. Add a north loop to support the industry adds about 5 miles and a south loop to the university adds another 3 for a total of 20 miles and perhaps another 16 stations.

One thing to point out is that 3 LRT lines share the same rail for 5 miles from river to I-205. So, while it has route miles, rail miles and coverage area are smaller.

 http://trimet.org/maps/railsystem.htm

Eric

[Jack Slade]

When you just look at the # of stations and calculate that each one can handle 500 vehicles per hour it is obvious that 20,000 vehicles are moved in an hour.  Since a lot of commuters use transit in pairs this would be 28,000 passengers per hour if we use the 1.4 average that statistics show.  Some of those people using the Tri-Met stations ar just transfers that might be on another route with a proper PRT grid.

 

Jack Slade

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[Eric Johnson]

Didn't we see a story where TriMet had a fare free zone in this downtown area that they recently discontinued and ridership dropped by like 20% or so? If so, that changes the demand for the system and this core area by a substantial amount.

Eric

[eph]

Yes, ridership has dropped if you look at 2012 data.  I just don't have station by station numbers for those.  Also, it is fair to say that the system was operating at that level, so Podcars should match it.  Plus I expect Podcars to be popular, but fare adjustments can take care of that aspect with the money going to expand the system possibly.

I will post the speadsheet and google earth files for verification and what-ifs when I get some results.  In particular I would like to consider a mix of PRT and GRT, trains and reduced headways.


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[eph]

Found this reference to peak volumes for Portland:
http://www.publicpurpose.com/ut-lrt-pk.htm
" In Portland, for example, inbound (toward downtown) light rail volume averages approximately 1,100 per hour during the 6:00 a..m. to 9:00 a.m. peak period."

A linked 2-car Podcar system in GRT mode could move 8 passengers and even with headways of 3 seconds would top out at 9,600 pphpd.  This is WAY beyond the levels needed for Portland.  Single GRT-mode Podcars could move up to 4800 pphpd.


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[Eric Johnson]

A simpler way to look at this is a normal PRT system with 1.3 average riders per pod and 3 second headways (1200 * 1.3) is 1560 pphpd. It even works with 4 second headways (800 * 1.3=1040).  This is before you add in capacity enhancements like reduced headways, higher rider share, and platooning.
Eric

[eph]

If you want to remove skepticism, presenting numbers that exceed most demand scenarios and using existing technology is a good way to do it.  So the GRT case using Podcars.


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[Eric Dunn]

Is the discussion of capacity really the be-all and end-all?

Wouldn't the bigger selling point be he ease of servicing buildings and neighbourhoods?

Interesting to note that the Chicago tunnel company went bankrupt not because of line capacity, but the cost of connecting buildings to the system (in part as other economic factors were also working against them).

[eph]

No, it's not the only factor, but it's the one that gets PRT locked out by many/most transit feasibility studies.  That's why Podcars are important, because it's operating mode is flexible and capacity isn't an issue.


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[Eric Johnson]

You could easily bring both numbers to the table saying how PRT can handle today's ridership counts with fairly safe assumptions then show how there is plenty of room to grow for the future. The best way to show this info would be chart format.

Eric

[eph]

Absolutely.  Could even offer free premium PRT service for members of council.


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[Eric Johnson]

At least it wouldn't cost much! LOL...

Eric

[eph]

average cost per weekday ride, winter 09-10
MAX Yellow Line    $2.29
MAX Red Line    $2.03
MAX Green Line    $1.96
MAX Blue Line    $1.74
https://docs.google.com/spreadsheet/ccc?key=0AtsiMKlWupv0dC1hdW5lNVFwT2tZZVExQ0VWY2NYRXc#gid=0

Given a length of about 8 miles which includes overlapping with green and blue lines, can a replacement Podcar system be profitable?

Further, LRV could be sold to generate capital.
Stations could be reused.
Electrification is already in place.

Weekday Ridership: about 16,400 * 250 weekdays * $2.00/boarding = $8.2 million
Leverage at 5% payback, maxes out at a capital expense of $164 million leaves weekend ridership to cover O&M

$20 million per mile!

Using previous ratios, a peak of about 1640 boardings per rush hour  average trip length, maybe 5 miles, so each Podcar does about 5 trips per hour, so 1640/5 = 328 Podcars, less if GRT mode is used.

Yellow line has 21 stations

Maybe replacing LRT actually makes sense?


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