[LINK] more myki woes

[Tom Worthington]

Jan Whitaker wrote:
> ... must be some volume contention going on, either on a 
> network if self-contained on the tram or bus ...

I tried the demonstration Myki system at Southern Cross Station:
<http://www.tomw.net.au/blog/2007/05/victorian-public-transport-contactless.html>.

This is a contactless smart card with readers at the doors of trams and
buses. You swipe the card past the reader at the start and end of your
journey, described in the article as "... touch-on and touch-off speeds
...". The article also mentions touch speed of one second, which seems
to me to be unacceptably slow for a tram load of people getting on and 
off at a major stop.

I assume the readers are self contained, not requiring a data link.
Therefore the process should not be subject to network or peak hour
delays. However, the complex charging system will have to be loaded into
every reader on every tram, train and bus. This is likely to be causing
the problem with speed.

There are more complex readers at stations for checking your card
balance and ATM-like units for loading the cards with money. These would
likely be networked and so more subject to network delays.

The system in Istanbul is a much simpler "touch in" one 
<http://www.tomw.net.au/travel/istanbul.shtml>. There is a
fixed price for a ride which is not dependent on distance or time. You
are debited at the start of the journey and so do not need to touch in
again at the end. This has several advantages for implementation: you
don't need a complex fare system in the readers: one touch debits one
fixed fare unit. You don't need the system at the end of the journey, 
halving the load on the readers and  reducing the performance 
requirements (it is much more annoying being delayed when getting off a 
tram than when getting on).


-- 
Tom Worthington FACS HLM, TomW Communications Pty Ltd. t: 0419496150
PO Box 13, Belconnen ACT 2617, Australia  http://www.tomw.net.au
Adjunct Lecturer, The Australian National University t: 02 61255694
Computer Science http://cs.anu.edu.au/people.php?StaffID=140274