Comments on: Episode 1 – Introduction and Traffic Signals http://www.talkingtraffic.org/2007/08/06/episode-001/ Traffic, Transportation, and Mobility issues for the Everyday Person Fri, 18 May 2012 17:08:06 +0000 hourly 1 http://wordpress.org/?v=3.2.1 By: Talking Traffic » They’re Using That Term Again http://www.talkingtraffic.org/2007/08/06/episode-001/#comment-16 Talking Traffic » They’re Using That Term Again Wed, 25 Feb 2009 14:48:47 +0000 http://www.talkingtraffic.org/index.php/2007/08/06/episode-001/#comment-16 [...] I discussed the difference between “synchronized” and “coordinated” in the v... Unfortunately, they’re using the term in an egregious manner in this story. When the square is gridlocked, the system activates green lights for traffic heading out of town. But in the meantime, traffic heading toward town can be sitting at a red light wondering whether oncoming traffic is breaking the law. [...] [...] I discussed the difference between “synchronized” and “coordinated” in the v… Unfortunately, they’re using the term in an egregious manner in this story. When the square is gridlocked, the system activates green lights for traffic heading out of town. But in the meantime, traffic heading toward town can be sitting at a red light wondering whether oncoming traffic is breaking the law. [...]

]]> By: Episode 8 - Signal Detection & Operation : Talking Traffic http://www.talkingtraffic.org/2007/08/06/episode-001/#comment-15 Episode 8 - Signal Detection & Operation : Talking Traffic Tue, 15 Jan 2008 05:01:37 +0000 http://www.talkingtraffic.org/index.php/2007/08/06/episode-001/#comment-15 [...] back in the first episode of Talking Traffic, I explained the definition of the word “Actuation” as it refers to traffic signals. [...] [...] back in the first episode of Talking Traffic, I explained the definition of the word “Actuation” as it refers to traffic signals. [...]

]]> By: Chris http://www.talkingtraffic.org/2007/08/06/episode-001/#comment-14 Chris Sun, 19 Aug 2007 18:02:08 +0000 http://www.talkingtraffic.org/index.php/2007/08/06/episode-001/#comment-14 You have a good radio voice. Or should I say computer voice? Or handheld personal compressed audio player? Whatever. Nicely done and keep it up. You have a good radio voice. Or should I say computer voice? Or handheld personal compressed audio player? Whatever. Nicely done and keep it up.

]]> By: Mike (2) http://www.talkingtraffic.org/2007/08/06/episode-001/#comment-13 Mike (2) Mon, 06 Aug 2007 22:43:04 +0000 http://www.talkingtraffic.org/index.php/2007/08/06/episode-001/#comment-13 Nicely done Bill - I found it informative & interesting. I look forward to future podcasts :) Mike - speaking from personal experience - I assume the magnetic sensors used at intersections are similar to the magnetic loop sensors used at the drive-thru speaker post and they do indeed pick up bikes. Nicely done Bill – I found it informative & interesting. I look forward to future podcasts :)

Mike – speaking from personal experience – I assume the magnetic sensors used at intersections are similar to the magnetic loop sensors used at the drive-thru speaker post and they do indeed pick up bikes.

]]> By: Bill Ruhsam http://www.talkingtraffic.org/2007/08/06/episode-001/#comment-12 Bill Ruhsam Mon, 06 Aug 2007 21:01:30 +0000 http://www.talkingtraffic.org/index.php/2007/08/06/episode-001/#comment-12 Jim: Assuming (BIG assumption) that you have detailed knowledge of the traffic volumes flowing through an intersection, on a 24 hour basis, with changes during the weekend, holidays, football games, weather events, and whim, with that knowledge extending to precise left- and right-turning volumes, and with other information too detailed to describe, then yes, you can have a "right" answer; a solved problem. Realistically, no, there is no way to plug in the numbers and then go out and program the signal without tweaking it in the field. That is why signal technicians are a requirement of any municipality that wants to run its own signal network. There are models that can help, and they vary from simplistic deterministic (exact) models to complicated stochastic (random) ones, but you still have to sit and watch the signal operate in order to optimize it. Jim: Assuming (BIG assumption) that you have detailed knowledge of the traffic volumes flowing through an intersection, on a 24 hour basis, with changes during the weekend, holidays, football games, weather events, and whim, with that knowledge extending to precise left- and right-turning volumes, and with other information too detailed to describe, then yes, you can have a “right” answer; a solved problem.

Realistically, no, there is no way to plug in the numbers and then go out and program the signal without tweaking it in the field. That is why signal technicians are a requirement of any municipality that wants to run its own signal network.

There are models that can help, and they vary from simplistic deterministic (exact) models to complicated stochastic (random) ones, but you still have to sit and watch the signal operate in order to optimize it.

]]> By: Jim (Physics is Phun) http://www.talkingtraffic.org/2007/08/06/episode-001/#comment-11 Jim (Physics is Phun) Mon, 06 Aug 2007 20:24:13 +0000 http://www.talkingtraffic.org/index.php/2007/08/06/episode-001/#comment-11 Bill, Congratulations on podcast number one... I love it! This may be future topic fodder as well, but I might as well ask the question now. Are traffic models generally considered to be "solved"? That is, is there a non-chaos-theoretic "right answer" to the signal timing for an intersection or network of intersections? Inquiring minds want to know! Bill,

Congratulations on podcast number one… I love it!

This may be future topic fodder as well, but I might as well ask the question now.

Are traffic models generally considered to be “solved”? That is, is there a non-chaos-theoretic “right answer” to the signal timing for an intersection or network of intersections?

Inquiring minds want to know!

]]> By: Bill Ruhsam http://www.talkingtraffic.org/2007/08/06/episode-001/#comment-10 Bill Ruhsam Mon, 06 Aug 2007 19:56:45 +0000 http://www.talkingtraffic.org/index.php/2007/08/06/episode-001/#comment-10 <p>Mike,</p> <p>With respect to your question, I'm told that most bikes will trip the loop sensors in the pavement, as long as they aren't multi-thousand dollar race bikes with mostly composite frames. </p> <p>As for your future topic, the discussion of signal phasing, i.e. what order the various arrows and directions come up in, is definitely an entire episode, if not two. As for pros and cons, it just depends. I'll note this down for a podcast.</p> <p>I'll think about the wiki idea. Thanks for the suggestion.</p> Mike,

With respect to your question, I’m told that most bikes will trip the loop sensors in the pavement, as long as they aren’t multi-thousand dollar race bikes with mostly composite frames.

As for your future topic, the discussion of signal phasing, i.e. what order the various arrows and directions come up in, is definitely an entire episode, if not two. As for pros and cons, it just depends. I’ll note this down for a podcast.

I’ll think about the wiki idea. Thanks for the suggestion.

]]> By: Mike http://www.talkingtraffic.org/2007/08/06/episode-001/#comment-9 Mike Mon, 06 Aug 2007 15:17:08 +0000 http://www.talkingtraffic.org/index.php/2007/08/06/episode-001/#comment-9 Excellent first podcast. A question, a possible future topic, and a suggestion: Question: You mentioned bicycles when you talked about actuated signals. Do most bikes have enough metal content to trip the magnetic sensors in a typical intersection? Or are there actuated bike lanes that I'm not aware of? Future topic: One thing I've noticed since moving to Michigan is that left turn signals operate differently than most places on the East Coast where I have previously lived. Dedicated left turn arrows illuminate following the green cycle for the road as compared to before the main road gets their green. When the main road has a green, the left turn signal flashes red, indicating left turn is authorized contingent on oncoming traffic. Any thoughts on the pros and cons of the two different modes? I must say that I have found traffic to flow better the Michigan way - fewer vehicles get stuck in the intersection having to take left turns after the light has technically changed. Suggestion: It would be lovely to start compiling a wiki (or link to a pre-existing one) to keep track of the terms you introduce. It could be indexed to the podcasts in which the term is most highly relevant. Excellent first podcast. A question, a possible future topic, and a suggestion:

Question: You mentioned bicycles when you talked about actuated signals. Do most bikes have enough metal content to trip the magnetic sensors in a typical intersection? Or are there actuated bike lanes that I’m not aware of?

Future topic: One thing I’ve noticed since moving to Michigan is that left turn signals operate differently than most places on the East Coast where I have previously lived. Dedicated left turn arrows illuminate following the green cycle for the road as compared to before the main road gets their green. When the main road has a green, the left turn signal flashes red, indicating left turn is authorized contingent on oncoming traffic. Any thoughts on the pros and cons of the two different modes? I must say that I have found traffic to flow better the Michigan way – fewer vehicles get stuck in the intersection having to take left turns after the light has technically changed.

Suggestion: It would be lovely to start compiling a wiki (or link to a pre-existing one) to keep track of the terms you introduce. It could be indexed to the podcasts in which the term is most highly relevant.

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