Ryan T. Wilson
Post Number: 4
|Posted on Monday, June 22, 2009 - 05:31 pm: |
I have noticed that some traffic signals in Frisco are placed on the corners and some are in the medians. I can understand this at some intersections, but at others (i.e. Rolater/Independence), it seems like the pole could easily be at the outside corner. Just out of curiosity, why is this?
Perry Harts, Moderator
Post Number: 111
|Posted on Wednesday, July 01, 2009 - 08:46 am: |
Thank you for your question.
The permanent signal poles are usually located in the corners of the intersection. That is our desired location, but there are occasions where underground and/or overhead utilities may be in the way. The right-of-way adjacent to the roadway is typically 11 to 12 feet wide. This area is generally used for utilities and traffic signal equipment. In the case of overhead utilities, we can usually have those raised or relocated so we can remain in the corner. When it comes to underground utilities or storm drains, it is sometimes cost prohibitive to have those things moved. The foundations for the traffic signals poles will have a depth that ranges from 13 feet to 22 feet. The foundations have a diameter that ranges from 36 inches to 48 inches.
At Independence and Eldorado, the traffic signal pole for the northbound direction is being located in the median because Independence is not completely finished. We do not have mast arms long enough that can extend from the far northeast corner to where cars will actually be driving. We could have installed two wood poles with temporary spans, but we chose to locate the signal pole in the future median to reduce cost. When Independence is widened, we will simply rotate the existing pole and will not have to install any other equipment. This change saved us about $10,000 to $15,000.
Assistant Director of Engineering Services/Transportation