Ada County Highway District

ACHD's Road Wizard Sunday, May 5, 2019 ACHD's Road Wizard

Dedicated left-turn time requested to 8th Street from State Street; stakes and orange tape are signs of early Chinden Boulevard widening efforts; pothole filled in odd pavement area at Fairview Avenue and Whitewater Park Boulevard

The Road Wizard Replies

Dear Road Wizard: Turning left onto 8th Street from State Street is never fun, but it's nearly impossible during the evening commute. Cars back up, maybe one or two make it through each signal, and some make the dangerous and illegal turn through the parking lot of the old bank on the corner. Given that there's basically two ways into the North End (at 15th and at 8th), couldn't we please get a dedicated turn light at 8th?


Road Wizard:

ACHD recently evaluated adding a separate eastbound left-turn phase to go with the left-turn lane at this intersection. In Downtown Boise, however, signalized intersections operate on a "fixed time" system, which makes that challenging. All things considered, this timing approach is one of the most efficient ways of accommodating traffic flows in an area with closely spaced signalized intersections.

Planning the same amount of green time in the same pattern by time of day also allows drivers to progress through downtown while still allowing enough time for pedestrians to cross the street.

One seemingly small change, such as the introduction of left-turn signals, can have far-reaching impacts on how the signals interact. In other words, if time is added for a left-turn phase, that has to be taken from another direction of traffic that may experience significantly longer delay as a consequence.

A left turn signal for State at 8th Street may reduce delay for this specific movement, but it sacrifices traffic progression along State and introduces delay to other parts of the system. At this specific intersection, a left-turn arrow would have significant consequences.

But there is good news for signal timing in the area. ACHD updated timing throughout Downtown Boise in 2017 (about 130 signals). An analysis which was done after the revised signal timings went into effect found a travel time reduction on State between 5th and 18th streets in the peak travel direction of between five and 10 percent. This amounts to an average of about 20 seconds of time saved per vehicle during rush hours.

Dear Road Wizard: I was traveling down Chinden Boulevard today, westbound from Eagle Road, and noticed on the south side that there are many stakes with orange tape things, going down to Locust Grove Road. Is this, hopefully, a sign that the widening to four lanes is about to start?


Road Wizard:

There are many "starts" in major road projects. The stakes indicate the start of right of way purchases along Chinden/U.S. 20/26 in preparation for the Idaho Transportation Department's widening of the rural/not-rural-for-long route between Boise and Caldwell.

The start of actual construction is planned for early 2020. That same year, ITD will build additional lanes from Meridian Road to Highway 16. The section between Meridian Road to Locust Grove Road is planned for 2021 construction.

Dear Road Wizard: Does ACHD own the pavement just north of Fairview Avenue and west of Whitewater Park Boulevard? The pavement is in very bad condition with at least one very large pothole. This pavement is an access to the Greenbelt and multiple businesses including the Cottonwood Suites motel and functions as an alley. How about some love for that section?


Road Wizard:

ACHD owns/maintains some of this odd paved area, which provides the businesses along the river public street access. ACHD filled the pothole this week, but the rest of the pavement is not high on the work list.

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