Pie Chart Traffic Light
by Jon Peltier
Thursday, May 29th, 2008
Peltier Technical Services, Inc., Copyright © 2010.
Licensed under a Creative Commons Attribution-Noncommercial-Share Alike 3.0 Unported License.
The information aesthetics blog described an interesting use for a pie chart: directing traffic. In marshalite alternative traffic light, there was a picture and short description.
“an alternative, rotary traffic signal designed by Charles Marshall in 1936 & used from the 1940s through 1970s in Australia. 2 rotors pointing at colored sections denote whether traffic in either direction should proceed, prepare, or stop. based on a traditional clock face, it has the advantage of clearly showing signal phase timing.”
This type of signal has advantages and disadvantages:
- advantage: shows the timing of the green-amber-red cycle
- disadvantage: transition between phases is not as distinct as changing lights
- disadvantage: doesn’t allow for sensor-driven dynamic timing
- disadvantage: mechanical devices are typically more prone to failure than electronic ones *
* probably not a factor in 1936
The photo came to information aesthetics via Wikipedia.
Photo Copyright © Dysprosia, all rights reserved. Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met:
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Posted: Thursday, May 29th, 2008 under General.
Comments: 9
Comments
Comment from derek
Time: Friday, May 30, 2008, 1:59 am
I would have preferred that instead of the colored disk being fixed behind a rotating indicator, the disk had rotated behind a fixed mask, so that only one color was visible at a time.
Comment from Jon Peltier
Time: Friday, May 30, 2008, 6:41 am
Derek – That sounds like the traditional colored light signal. I think that would eliminate the benefit of seeing the overall cycle, without eliminating any of the drawbacks.
Comment from Tony Rose
Time: Friday, May 30, 2008, 9:05 am
Did they use Xcelsius to make that? ;)
Comment from Rod McInnis
Time: Friday, May 30, 2008, 1:42 pm
You can’t post something like that without instructions on how to duplicate it in Excel!
Comment from Eric
Time: Friday, May 30, 2008, 1:58 pm
In several Chinese cities, countdown clocks beside vehicle traffic signals (but interestingly, not pedestrian walk signs) are common at super-congested intersections.
Comment from Jon Peltier
Time: Friday, May 30, 2008, 2:03 pm
Eric -
You see countdown timers on pedestrian signals now very frequently in the States, so they know how much longer they have to get across and the drivers know when to start revving their engines.
Comment from Jon Peltier
Time: Friday, May 30, 2008, 2:05 pm
@Rod “You can’t post something like that without instructions on how to duplicate it in Excel!”
You need some electric motors, wire, sheet metal, screws, and paint…
Comment from Eric
Time: Friday, May 30, 2008, 3:54 pm
Jon,
Here in Canada, we have those pedestrian clocks too, but, in many cases, there’s not much of a relation between when the traffic light goes green and when the pedestrian clock reaches 0.
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