Two projects caught my eye in Pierce Transit's Transit Development Plan. In the capital projects section of Pierce Transit's budget it describes two major projects. One is the Pacific Avenue Transit Signal Priority project and the other is entitled Downtown Tacoma Transit Signal Priority II.
Each of these projects are quite exiting. The Pac Ave project will upgrade the traffic signals and other technology improvements on a 17 mile stretch of Pacific Ave extending from Downtown all the way to 224th. The signals will be fully capable of implementing Transit Signal Priority and some other technology upgrades include the installation of traffic counting and monitoring devices.
The Downtown project is a quite ambitious project that aims to "design and implement a comprehensive intelligent signal upgrade for Downtown Tacoma". The area of this upgrade stretches from Portland Ave in the east to Sprague ave on the west and from I-5 in the South to Division St in the north. In total about 80 signals.
According to Pierce Transit Spokesman Lars Erickson, the majority of the funding for these projects comes from grants. The projects are funded by grants from the FTA under the Congestion Mitigation and Air Quality (CMAQ) Improvement Program and also from WSDOT's Regional Mobility Grant Program.
As a traffic engineer I am pretty excited for Tacoma because of these projects. From fairly basic observations it seems that nearly all signals operate on a fixed time cycle. This means that regardless of varying levels of traffic, most of the signals will still operate on the same schedule. This type of configuration is archaic compared to what is possible with modern traffic signal controllers.
Another major problem is how Tacoma Link progresses through the signals. Now it's not a problem for Tacoma Link because way too much time is given for the train to pass, but that extra time causes problems for other modes of transportation. Also a problem is that after the train has passed, a circuitous recovery pattern begins that can leave vehicles waiting for a green light for excessive amounts of time. With the new upgrades the signals will hopefully be able to detect exactly when the train has passed the intersection and then gracefully recover to normal cycles afterwards.
And one more item that particularly bothers me, but probably nobody else notices, are the signal cycle lengths. The cycle lengths in downtown Tacoma are long for a dense downtown area. While I don't have exact figures, I would estimate that downtown Seattle or downtown Portland each have a cycle length of roughly 60 seconds. With the aid of a stopwatch I observed that the cycle length in downtown Tacoma is 100 seconds. That extra time means that drivers and pedestrians alike have to wait that much longer for the light to turn green again.