Showing Tag: "left" (Show all posts)

Protected Permissive Left Turns

Posted by Steve Fitzsimons on Wednesday, July 16, 2014, In : For Traffic Signal Designers 
Mid-sized and smaller cities have frequently chosen to provide protected left turn phasing on main street approaches of signalized intersections, citing a belief that it provided safer operations.  Recently however, this traditional belief has been challenged for a variety of reasons.  An option that combines protected phasing with permitted phasing emerged and is starting to see deployment.  Also, federal research identified a new approach in the signal display, using a flashing yellow arrow...
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Permissive Left Turn Conversion

Posted by Steve Fitzsimons on Monday, November 23, 2009, In : For Traffic Signal Designers 

Question:  My City has a traffic signal with a protected left turn that is to be converted to a permissive.  There is a mast arm for this move which currently has a signal heads for the left turn phase and through phase.  I have been told there is a product available from Pelco called the Astro-Brac that I can use to replace both the existing heads with one doghouse head, and mount it in between the current head locations.  What more can you tell me? 

Answer:  Pelco has a product called AB-0...


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Left Turn Signal Head Placement

Posted by Steve Fitzsimons on Thursday, July 16, 2009, In : For Traffic Signal Designers 

Question:  For left turn signal heads, we usually install it on the mast arm and the far side 1-b pole.  The MUTCD requires a 40 degree viewing angle from the left turn lane.  There are situations that the far side left turn signal head is outside the 40 degree angle zone due to the width of the street.  I know Caltrans doesn’t like to put the 1-b on the median too.  We required to have at least two signal heads for each moment.  So, what’s your opinion for the second left turn signal hea...


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About Us


Steve Fitzsimons If you would like to ask a question about driving rules, traffic signals or street lights, send your questions to: SFitzsimons@W-Trans.com or call 650-314-8313. Steve Fitzsimons is a professional Civil Engineer and Traffic Engineer in California. He is a principal at W-Trans. Find out more about W-Trans at www.w-trans.com **** If you need a traffic signal design or review, W-Trans is available for hire. If you are an electrical contractor, W-Trans is available for hire to prepare timing plans or traffic control plans.

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