Flashing Yellow Arrow, a Center Turn Lane, and a HAWK Beacon
At 4:40 p.m. on a five-lane arterial in Boise, you are southbound in the painted center two-way left-turn lane, preparing to turn left into a shopping center 250 feet ahead. Traffic both ways is heavy and stop-and-go. At the next intersection, the left-turn signal displays a flashing yellow arrow while the through lane shows a green ball. One block past the shopping center, a pedestrian hybrid beacon (HAWK) at a marked midblock crosswalk lights up: flashing yellow, then steady yellow, then steady red for you, while a pedestrian steps off the curb. A cyclist is riding the bike lane to your right, and the dashed white line marking the bike-lane approach has just ended, replaced by solid white. Your passenger suggests staying in the center lane for the next half mile to get around the stopped traffic.
1. What does the flashing yellow arrow permit, and what must you do before completing the turn? Contrast it with a steady green arrow and a steady red arrow.
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Flashing yellow arrow = permissive left. You may enter the intersection and turn, but only after yielding to oncoming through traffic and to pedestrians in the crosswalk. The arrow tells you the movement is allowed, not that it is protected.
Key contrasts:
- Steady green arrow: protected. Oncoming traffic is stopped by its own red, so you proceed without yielding to vehicles - but still watch for pedestrians and for drivers who run their red.
- Steady red arrow: the movement is prohibited; remain behind the stop line. Do not treat it as a yield sign.
- Flashing yellow arrow ending in steady yellow: prepare to stop. Do not assume oncoming traffic will stop just because your arrow changed - the yellow-trap crash happens when a left-turner commits on yellow while an oncoming truck is still coming through on its own yellow.
In this setup the through light is also green, so oncoming traffic is definitely moving at 40-plus feet per second. Creep forward only as far as needed to see, and turn only into a gap you can complete in - do not stop in the oncoming lane.
2. Can you use the two-way left-turn lane as the passenger suggests - riding it for half a mile to bypass stopped traffic? Explain what the lane is for and how the bike-lane marking matters.
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No - that is illegal and dangerous. A two-way left-turn lane exists for one purpose: decelerating into a left turn, or completing a left turn from the opposite direction. It is a turn bay shared by both directions, which is why it is marked with two yellow lines and inside dashed yellow lines.
Problems with the suggestion:
- Travel or passing in it is prohibited. Using it as a queue-jumping lane for 2,600 feet is travel, not turning.
- Head-on exposure. Every northbound driver planning a left turn expects that lane to be empty and will pull in while checking only for oncoming traffic - you would be sitting in their path.
- The markings tell you the same thing. The solid white line now separating the bike lane signals that crossing is discouraged and that the cyclist has a predictable path; swinging right across it at speed, from a lane where no one expects a right-turning vehicle, sets up a right-hook crash.
Enter the center lane only when you are close enough to begin the turn, check the cyclist, signal, and cross the bike lane at a sharp, slow angle.
3. Describe exactly what each phase of the HAWK beacon requires of you as you approach, and how it differs from a railroad flashing red.
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HAWK sequence, in order:
- Dark: no pedestrian has activated it; proceed normally.
- Flashing yellow: a pedestrian has pushed the button. You may proceed if you are past the point of safely stopping, but you should be slowing and preparing to stop - it is not a green.
- Steady yellow: stop if you can do so safely.
- Steady red: stop and stay stopped at the crosswalk. This is a full stop, not a yield.
- Flashing red: stop, then proceed if the crosswalk is clear. Treat it like a stop sign once the pedestrian has cleared your lane.
Why it differs from a railroad signal: the HAWK can show flashing red to drivers while the pedestrian is out of the roadway - the flashing phase is what lets traffic resume without waiting for the whole cycle. A railroad flashing red means a train is coming; you never "stop and proceed" into a crossing with an active train signal. Same color, different logic.