Control Matters
SPLat Controls' aperiodic newsletter

16 Jul 2009
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Welcome to our new look newsletter. I hope to be able to do these reasonably frequently. They will contain not only SPLat-related product news, but also stuff I hope anyone with a general interest in controls and technology matters will find of interest. I welcome your feedback.

David Stonier-Gibson.

In control - Stuff about or related to control systems

Traffic control

Many years ago I designed a magnetic loop vehicle detector for traffic light systems. My design was used throughout the state of Western Australia from about 1970 to 1985. Ever since that time I have had a passing interest in the problem of traffic light control. How can traffic lights be made smarter, for improved traffic flow and reduced wait times? I am also interested in algorithms and heuristics in general, meaning how to devise and program common sense rules of thumb. Some work being done at the Dresden University of Technology in Germany is very interesting, as it finds that two different traffic control heuristics that individually produce poor results can produce very good results if combined. You can read more here.

Out of control - Nothing much to do with controls, (but interesting)

Calculating Apollo trajectories 

40 years after Apollo 11 (the landing being one of the 3 world events about which I will never forget where I was at the time - the other two being JFK's assassination and 911) I just read an article written by Jack Crenshaw, who did the trajectory calculations and designed some of the programs that ran on 1MHz computers. Jack Crenshaw also happens to be one of the gurus of embedded systems, especially in the area of math algorithms. Read his article here. The 2nd paragraph of page 3 sent shivers up my spine. This is better than any movie!

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© Copyright 2009 SPLat Controls Pty Ltd. This communication does not constitue professional advice


About 15 years ago, living in Asian traffic (enough said), I was overwhelmed with the desire to develop a traffic management system that addressed the needs of the roads authorities, yet operated in a flexible way to satisfy the drivers, riders and pedestrians.
The results was a software simulation of CARS (computerised adaptive routing system) which turned the current sensing and route algorithms on their head.  The basic premise was to detect vehicle count as they leave the junctions (not on the approach apron), and to allow dynamic control of lane turn arrows to adapt with traffic volumes.
Some other tricks were also applied to allow real-time unattended modification of the traffic flow - based on local surges (e.g. stadium crowds), and to close specific routes for roadworks, or other priority activities.
The simulation result was spectacular, and when demonstrated to traffic engineering firms (UK and Germany), they loved the idea, but noted that a small number of blue-chip companies have a stranglehold on these infrastructure projects which usually have an installed life of 20-30 years, and it would be near impossible to get a look-in unless you exposed the IP to them so they could 'think about it'.
Oh Well - it was only developed for fun in the first place. If they want me to talk, they can hire me as a consultant and I'll show them how it works!
Many thanks,
Michael COOP
SL4P pty ltd
Michael, thanks for that. The blogg hasn't worked for us, so this new newsletter is the replacement. I can't persuade people to use RSS feeds!
Sounds like you were "up against it" with the traffic control algorithm. Nothing new in that. :-(  Brawn beats brains. - David
Thank you David for bringing such an epic to all of us, I also read the linked Jack Crenshaw’s interview with great interest and enthusiasm, so much wisdom to be derived from this brave and insightful engineer/scientist - Shabbir
I'll enjoy reading that over the weekend. - David