January 18


Traffic Signals 101

By Mike Spack

January 18, 2012

Signals 101Here's a guest post from Max Moreland whose been working with me for about a year now.  Here is his take on the Traffic Signals 101 class he attended last week –

The course presented a broad view of traffic signals ranging in topics all the way from why they are installed to emergency vehicle preemption.  As an EIT working in the traffic engineering industry that has been out of school for about a year, I found this to be a useful course and would recommend it to those in a similar position to myself.

Since there was such a large range of topics presented in the course, there were plenty of things that I had already seen.  Some of these things were learned in school and other things I have picked up while working, but it was nice to see it all together in one course rather than in bits and pieces.

 Here are the top five things I learned at Traffic Signals 101:

  1. Signal Agreements – Who pays for what?  Traffic signals are expensive, so it is important to know how cost, maintenance and operations are split up.
  2. Signal Plans – If you are going to work with signals, you will need to know how to read a signal plan and a wiring diagram.  All those dots, lines and arrows are not just there to make everything look fancy and technical; they actually mean something!
  3. Flashing Yellow Arrows – These are starting to pop up all over the place and learning their proper function is very useful.
  4. Vehicle Detection – I remember talking about loop detectors in school, but I do not recall going into much detail on them.  Traffic Signals 101 gets into the different types of detection and detectors used in the field.
  5. Emergency Vehicle Preemption (EVP) – The operation of EVP lights is more complex than I had previously thought.  There is more to it than just detecting an emergency vehicle in the area.

The course is only offered once a year, but you can check out the course workbook on MnDOT’s website. Here's a list of the topics covered:

  1. Agreements
  2. Field Components
  3. Introduction to Plans
  4. Cabinet
  5. Controller Operations
  6. Field Operations
  7. Head/Loop Placement
  8. Pedestrians
  9. Advanced Warning
  10. EVP and Railroads
  11. Special Provisions
  12. Maintenance
  • That is a very nice summary of the 101 course. Thanks Max for the comments. The book on the web (linked in the article) is now the 2012 version.

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    Mike Spack

    My mission is to help traffic engineers, transportation planners, and other transportation professionals improve our world.

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