[aprssig] traffic reporting

[Jim Lux]

This is sort of interesting.  I read Bob's page on traffic, which is an
interesting approach to "detecting" traffic anomalies using APRS, although I
think that given the modern "intelligent transportation systems" (ITS),
there are better data sources available. Actually, both forms of reporting
(anomalies and regular old speed data) are useful.  Compare this to weather
stations on APRS.  They report fairly predictable data (temperature, etc.).
Then, you have some form of severe weather warnings as well.

The problem with reporting only anomalies is that it requires some local
knowledge.  This is the same problem with the traffic reports on AM radio.
They never tell you that the 10 is a parking lot, because it's ALWAYS a
parking lot during rush hour, so it's not news to a local driver.

However, if you are visiting from out of town, you wouldn't necessarily know
that. (I faced a similar problem driving near London last summer.  How was I
to know that the orbital is a giant parking lot these days, and that
alternate routes would be a good idea?  (Certainly the in-car nav system,
which worked fairly well, wasn't going to suggest back roads as an
alternate.)  That's where the overall reporting of speeds or road segments
comes in.  It would be a fairly substantial change to most APRS
applications, but the slick way to integrate this would be to change the
background map according to the data (much like you have a dynamically
changing radar image behind the APRS data).  In southern california, perhaps
the optimum scheme is just to periodically (every 5-10 minutes) broadcast
(an a FCC and copyright legal way, of course) the background image from
http://www.sigalert.com/ or from the Caltrans website as a standard packet
transmission.   Perhaps in pieces, spread over the 10 minutes, a'la
teletext, so you don't block all the other APRS traffic.

We should, however, be looking to more sophisticated in-car display
technologies than the small text/minigraphics display on a D7.  Lots of cars
do come with screens up front, and it's only a matter of time before someone
hacks the telematics system to figure out how to display extra data.  Even
now, they provide a video input on some (although there are some legal
restrictions that prompt disabling the video input when the car is moving).

There are commercial products that display traffic data (they're an option
on certain Acuras, for instance, and there's a PDA looking widget that
claims to do this too).  Maybe a better approach is to figure out how to add
APRS data to the traffic display device, rather than the converse?