From: whheydt@pbhya.PacBell.COM (Wilson Heydt)
Newsgroups: ba.transportation
Subject: Re: Alliance for a Paving Moratorium (Alert)
Date: 5 Jan 93 16:50:10 GMT
Reply-To: whheydt@PacBell.COM (Wilson Heydt)
Organization: Pacific * Bell, San Ramon, CA

In article <1530@dosbears> dosbears!mikel@pyramid.com writes:
>In article <1993Jan5.004707.15935@pbhya.PacBell.COM> whheydt@PacBell.COM (Wilson Heydt) writes:
>>Now let's *both* look at reality.  You've assumed two things--first
>>that trains *will* be run at the kind of headways you're talking
>>about.  While you are (no doubt) correct that CalTrain (per your
>>example) *can* run 5 minute or less headways--do they?  I seem to
>>recall complaints about 2 *hour* headways at some times of the day...
>
>If CalTrain upsets you, try BART.  2.5 minutes headways thru SF, 3.0
>minute headways in the rest of the system.  Claiming that CalTrain
>can do 5.0 headways is being generous, in my opinion.  BART not only
>can achieve those headways, they do -- right under a big 10 lane
>freeway.  CalTrain is not restricted by technological constraints.

Now that we've returned to a perennial topic here....  :-)

Yes--BART *can* do 2.5 minute headways.  Possibly it does during
commute hours in SF by counting trains arriving and departing to and
from 3 separate lines.  In practice, however, for an individual rider,
the headways are only that close between SF and Oakland-West--at best.
I find that the real, effective headways are 15 to 20 minutes.
(Believe me--having jsut missed one train departing Walnut Creek last
night because the feeder bus was running late, I waited the full 15
minutes.  I'd be *delighted* for that to have been 2.5 minutes, but
wishing it won't make it so.)

>>The second issue is that, while you have cited *average* occupancy for
>>cars, you've cited full seat occupancy for the trains.  If I took the
>>daily ridership on CalTrain and divided by the number of trains--the
>>figures for trains would be lower, and I assumed that every car seat
>>is full (say--an average of 5 per car?) the freeway value would be
>>much higher.  In such a comparison, a freeway lane would yield nearly
>>10,000 people per hour, and a 4-lane freeway would be 40,000 per
>>hour--20,000 each way, while the train would fall to--perhaps--600
>>per hour.  Aren't statistics fun?
>
>Just try to get more than 1.1 people/car.  Judging from some of the
>asocial people posting here, there would be bloodshed.  I think 1.5
>is probably an upper limit.

Nice dodge.  The question isn't "How can we increase private vehicle
occupancy?", but rather "Are *all* those trains full?"  If the answer
to that later question is "No", then capacities that assume they are
are highly misleading.  No one has argued that with the *vehicle*
capacity of a freeway lane.  Heck...  Many of us are willing to have
the rough computations assumme 1.000 people per car.  The bias creeps
in when you count passengers on the train *as*if*every*train*were*full*
rather than on average occupancy.

	--Hal
-- 
Hal Heydt                    |    
Analyst, Pacific*Bell        |            You!
510-823-5447                 |    Out of the Gene Pool!
whheydt@pbhya.PacBell.COM    |