On Sat, 14 May 2005, Dave Arquati wrote:

Tom Anderson wrote:
On Thu, 12 May 2005, Dave Arquati wrote:

A very impressive system would be to not only have accurate Countdown
information online and at stops, but also to have
dynamically-estimated journey times to destinations from that stop,
available both online and via Countdown at the stop itself.

Yes, this would be very cool, but the amount of effort it would
require to gather the traffic data, process it to produce congestion
forecasts (not entirely unlike weather forecasting - congestion is a
dynamic, nonlinear, mobile phenomenon), work out delays to services
and distribute this to every bus-stop would be substantial.

I don't (think I) mean forecasting congestion, as such... just using
data on current traffic speeds to estimate those journey times.

Ah, but that does involve forecasting - if you want to know about delays
that a 38 at Victoria might suffer when it gets to Hackney, you need to
have some idea of what the traffic is going to be like about 45 minutes
into the future.

On the flip side, it's quite likely TfL are already doing this forecasting
as part of their realtime congestion management work.

The data collectors are already out there in the form of on-bus AVL,
C-charge cameras, TfL traffic cameras, RAC info etc.

Is that network dense enough? The CC cameras are only in a ring round the
zone (and possibly inside it - but not much outside it) and TfL and RAC
cameras are only on major arterial routes. The AVL data, though, would
cover all the roads you needed to know about - pretty much by definition!

Integrating into the online planner would also, i imagine, be very
difficult - it's the sort of thing that sounds easy, but is often
fiendishly difficult in practice, since the planner software will be
built around the assumption of a static database, rather than one
which changes every minute.

That's true, but Journey Planner already integrates the existing
real-time info into journey suggestions.

Ah, didn't realise that. Okay, in that case, it should be pretty easy.

tom

--
We'll never win by being like them. Our best tactic is to be better. Better necessarily means different. -- Jon Rentzsch