Computer Failure Causes Gridlock In MD County

Uncle Rummy writes "A central traffic control computer in Montgomery County, Maryland failed early Wednesday morning, leading to widespread gridlock across the entire county. The computer, which dates to the 1970s, is the single point of unified control for all traffic signals in the county, which comprises a number of major Washington DC-area suburban communities. When the system failed, it caused all signals to default to stand-alone operation, rather than the highly-tuned synchronization that usually serves to facilitate traffic flow during rush hours. The resulting chaos is a yet another stark reminder of how much modern civilization relies on behind-the-scenes automation to deliver and control basic services and infrastructure. The system remains down Thursday, with no ETA in sight."

Comments

70s computer

[icebike]

Damn! 70s? Talk about Return on Investment.

The WashPost, in another article touts Fragile Technology.
I reach for my 70's era calculator and estimate the operational life of 34 years for this system. Some Fragility. Who or what at the Post has been there that long.

Wonder if its some ancient PDP version or an small IBM mainframe. The article is scarce on details. Parts for either are getting hard to find except in the scrap market.

Still you have to wonder why it wasn't ported to some other platform if nothing else as an exercise in disaster preparedness. Any commodity computer could do the job.

There is a lot of stuff like this still in service. I saw a PDP 8 monitoring turbines in a hydro Power station, and asked about where they get that fixed. The reply was it never broke down, but they had stockpiled 6 replacements, tested each yearly, just because they realized how old it was. Nobody knows exactly what it does anymore.

Re:And if they had been using roundabouts...

[fridaynightsmoke]

As a UK resident and driver in the true home of the roundabout, I wish to tell you that roundabouts are not a panacea.

Roundabouts work best for light to moderate traffic, where all 4 directions and all movements (left turn, right turn etc) are fairly equal in demand. For heavy traffic, they very quickly congest as traffic builds on the roundabout and blocks all entry. Indeed, round here most busy/large roundabouts have traffic lights on them as well, with varying degrees of success.

As for "gas consumption from forced arbitrary deceleration and acceleration is reduced" - I strongly disagree. Here roundabouts are used as a form of 'traffic calming', ie a deliberate obstacle to slow traffic. With a traffic light its a 50/50 chance between stopping completely and carrying on at cruising speed. With roundabouts there is always a decelerate/accelerate cycle, which depending on the design of the junction can be quite severe. In Birmingham (UK) and elsewhere. there was even a recent fad among local traffic engineers to plant high vegetation on the sightlines for approaching traffic to force all vehicles entering the roundabout to slow to below 5mph to be able to see traffic on the junction. On some examples here you have maybe 3 ft before the roundabout itself where you can see oncoming vehicles.

Don't get me wrong, I'm not saying that roundabouts are rubbish and traffic lights are good, but theres different solutions to different problems. Replacing non-synchronised traffic lights with roundabouts in a situation with very heavy traffic would have a very much worse result.