Ada County Highway District

ACHD's Road Wizard Sunday, October 7, 2018 ACHD's Road Wizard

Locust Grove and Franklin road intersection crosswalk is activated every cycle even without pedestrians; Coffey Street and Chinden Boulevard signal request; misleading sign at Avenue B and Jefferson Street

The Road Wizard Replies

Dear Road Wizard: I am curious why the northbound crosswalk at the intersection of Locust Grove and Franklin roads in Meridian often gets a walk signal even when there are no pedestrians. I have rarely seen pedestrians at this intersection in the two years I have been using it daily, but I have never seen it not get a walk signal. As a result, the north/south signal is often green long after the automobile traffic is through. It usually helps me get through, but I am curious about the logic behind it.


Road Wizard:

The green light may seem long for the sake of pedestrians, but the timing is set to benefit motorists. The signals on Locust Grove are coordinated to provide the best possible traffic flow, which means green time for north/south traffic is largely set with a fixed minimum amount of green time. The settings are based on the average number of vehicles expected to come through each signal cycle, though sometimes the green will last too long or not long enough.

Because there is plenty of time to provide a walk signal every cycle, the "walk" signal appears by default. There is no penalty to vehicular movements, since providing the indication doesn't change signal coordination, or the amount of time available for east/west traffic.

Dear Road Wizard: What are the chances of getting a traffic light from Coffey Street to Chinden Boulevard? It is very dangerous trying to get out onto Chinden.


Road Wizard:

Chinden is a four-lane arterial road with a shared center turn lane/left-turn lane, and Coffey is a lower volume collector street that has stop signs at Chinden. In a July column, another reader, "Joe" suggested restricting left turns from Coffey onto Chinden. Sometimes drivers on Coffey may want to turn left onto Chinden, while drivers on Chinden are waiting to make left turns of their own.

But crash records didn't support any changes, and restricting left turns would inconvenience people on Coffey. Plus, there are other locations nearby that are reasonable alternatives to turning left onto Chinden.

Signal installation is also not in the plans. The Coffey intersection is fairly close to the big Glenwood and Chinden intersection, so the location isn't ideal for a signal. Plus, there isn't enough traffic on Coffey to justify red light delays on Chinden, which is a major travel corridor.

Dear Road Wizard: Try driving north in the right lane of Avenue B toward the new Reserve Street roundabout. As you approach the Jefferson Street traffic light, you will see a painted straight arrow in your lane which seems to say that you are expected to continue across Jefferson. But on a post on the other side of Jefferson is a sign that has a curved arrow saying "right turn only." If the construction of the St. Luke's Children's Pavilion is ever finished, and the street restored to its original width, there may be a third lane, making the sign relevant. But until then it might be better to cover it with a bag.


Road Wizard:

This is a case of the sign/cart before the horse. Yes, there will be a northbound right-turn lane once the pavilion is complete next year. The signage does not match the current lane configuration, so ACHD removed the sign. It will return once the "right turn only" comes back into play.

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