Thursday, September 25, 2014

5 Points Lights Signal-Timing Adjusted After Recent Equipement Installation

We have heard from several drivers that the green light length, heading westbound on Sandpoint at 5 corners in NE Seattle has become significantly shorter since SDOT installed new traffic signal equipment at the end of July.

One email the Laurelhurst Blog staff received said:
Is it me or did the green light length, heading westbound on Sandpoint at 5 corners get significantly shorter? It seems as if they have changed the timing on the light and traffic is backing up all the way to hospital in the morning.

Here is the response the Laurelhurst Blog staff recently received from SDOT’s Traffic Signals group:
The signals were rebuilt and activated on August 24.  Although we attempted to maintain the previous signal timing as much as possible, we made some minor timing changes to improve safety at the intersection.  
These changes included increasing the clearance time for all phases, or movements, due to the size of the intersection as well as increasing the pedestrian crossing time at most of the crosswalks.  
These changes required making minor adjustments to the green time for all phases, as we needed to keep the existing cycle length in order to move east/west traffic.  (A cycle length is the amount of time it takes to serve all phases once).
One additional step in the installation was to configure and activate vehicle and pedestrian detection. While this process was occurring, the signals operated automatically and the main east/west through phases received less green time than they do normally.  
The intersection’s vehicle and pedestrian detection is now operating and westbound traffic should now have more green time. Our site visits have shown the signal to be operating much more efficiently.


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