Ada County Highway District

ACHD's Road Wizard Sunday, July 28, 2019 ACHD's Road Wizard

New striping on Main and Fairview; bike lanes in downtown Boise; right turn lanes at the intersections of Eagle and Chinden and Eagle and Franklin.

The Road Wizard Replies

Dear Road Wizard: Do the new lines on Fairview and Main make any sense to anyone? They look inspired by Piet Mondrian. Lanes shift, appear, and end. In places there are three or four solid white lines in parallel. In just a few days I've seen cars and bicycles using about every possible combination. Like Trafalgar Square, or any modern art piece, it seems everyone is entitled to their own interpretation and the intent of the artist is known only to himself.


Road Wizard:

This portion of pavement resurfacing--and subsequent markings-- were planned out well in advance. Sometimes what goes down on paper doesn't always translate so well onto the actual roadway. In this case, the markings were off one lane width, when maximum lane shift allowed by ACHD is only half of a lane width. To remedy the issue, ACHD plans to remove the confusing markings. By itself it is a simple process, but because a micro seal was just recently placed, they are unsure how obliteration will affect it. They will experiment with this process this weekend and determine the next course of action. If the micro seal is negatively affected by the obliteration, they will have to try a different solution.

Dear Road Wizard:  I've noticed that some of the bike lanes in downtown Boise have interior lines and others don't.  Also, when there are interior lines sometimes, they disappear in front of alleys and driveways, which means cars entering the roadway don't always know that they're crossing a bike lane. Is there a standard for this?


Road Wizard:

Where there are bike lanes next to on-street parking, ACHD installs two parallel stripes. The "outside" stripe closest to the lane of motor vehicle traffic is wider and delineates the bike lane as a separate space on the roadway specifically for bicycles. The "inside" stripe closest to the curb shows where bike lanes are separate from on-street parking. Inside lines are generally absent on streets where they intersect alleys and driveways to dissuade motorists from parking there. In some areas, where the City of Boise has installed parking meters, "tick marks" are present that delineate individual parking spaces. The "tick marks" also save on paint costs compared to inside lines and are an optional, though still appropriate, treatment.

Drivers exiting driveways or alleys have the same obligation to stop for vehicles, both motorized and not, as well as pedestrians. The presence or lack of striping doesn't change this.

Dear Road Wizard: With all of the road work that has been done to Eagle Road over the years, why have they never put right turn lanes as you travel south at the intersection of Eagle Road and Chinden Boulevard, and at the intersection of Franklin Road and Eagle Road?


Road Wizard:

It is important to note that Eagle Road (State Highway 55) and Chinden Boulevard (State Highway 20/26) are not ACHD-maintained facilities. They are state highways which fall under the Idaho Transportation Department's (ITD) umbrella.

Right turn lane installation on existing roadways is not always as straightforward as one may think. This is especially true when right-of-way must be acquired for construction. That is the case with Eagle Road/Chinden Boulevard intersection. However, ITD does have long-term plans to reconstruct this intersection as a Continuous Flow Intersection, or CFI. CFIs are new to Idaho, but quite a few have already been constructed by the Utah Department of Transportation in the Salt Lake City area. The first of these in the State of Idaho will be built at State Highway 44 and State Highway 55 (south of downtown Eagle) as early as next year.

For Franklin Road, there are plans to add a third southbound lane on Eagle Road from Fairview Avenue to Franklin Road, but it is unclear if those plans include a separate southbound right turn lane at Franklin Road.

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