On Sat, 10 May 2008 19:42:03 -0700, "Jack May"
wrote:



Your irrationality is that you think all the passengers get out of their
cars to use the LA rail system. Transportation people, especially in LA
have found that people are not getting out of their cars to ride rail
transit.

Instead they find that a very high percentage of the people are already
using transit and just switch to other transit systems when they open
because of an advantage in getting to work cheaper, faster, better than the
transit system they were using. So building new transit systems tends to
not decrease car traffic.


Wading into this late but still...

The statement above presupposes that the only measure of success of
public transport investment is whether it gets people to switch out of
their cars. In practice, in a place where cars account for quite a
small minority of travel (such as Inner London) investing so that
people switch from one mode of public transport to another cheaper,
faster mode, sounds a good deal, especially if it results in
alleviating congestion. As I understand it, a lot of the cost-benefit
analysis for transport investment in London, going right back to the
Victoria Line in the 1960s, recognises this, though I'm very happy to
be corrected on the specific point.

We know that people select their mode of transportation by going with the
one that is lowest cost to them mainly in their perceived value of their
time. Since cars typically are a faster mode of transportation than
transit,

That's far from a universal truth, and also depends on the time of
day. A city banker living in Oxshott and starting work at 9am would
have a quicker morning commute by train than by car.

exceedingly few people will get out of their car to use a new
transit system because they value their time far too highly to use a slow
transit system.

The gut level cost of a trip has been determined by economist to be:

Total trip cost = out of pocket $'s + time outside the vehicle (waiting,
walking) * hourly income + tune inside the vehicle * hourly salary /2


There are other variables - you might want to work during your journey
(admittedly not on a crowded short-distance train) so choose public
transport, or you might be carrying something heavy so use a car.
Also, of course, many people park-and-ride, driving to a station and
getting a train in from there.

Also, as I mentioned, time of week is an issue. I own a car but, like
most Londoners, rarely drive it into the centre of London. The
exceptions are certain times at weekends and in the evenings when I
know that traffic will be light - so driving is quicker - and parking
will be straighforward.

Just go ask some of your friends why they do not use transit. You will
find that most of the time they will say transit just to long to use to get
anywhere. There are effectively saying that their time is too valuable to
use slow transit system.

.... or they might be saying that they'd use public transport if a
convenient link existed

Poor people don't place a high value on their
time which is why so many of them use and have used transit for almost all
of their life, not just when a new transit line start operation.

Of course since you use transit you are probably not financially well off
either.

OK - this patently doesn't apply to London, where a lot of public
transport caters for an affluent clientele, and where many of the
highest-paid employees - like my example of the banker living in
Oxshott - work in areas where very few people commute by car.

So your analysis may or may not be valid in LA - I don't know enough
about the geography there to debate the point - but certainly wouldn't
apply in or around London.

Martin