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Bike News Roundup: What causes traffic congestion?

It’s time for the Bike News Roundup! As always, this is an open thread.

First up, Streets MN recently posted a video we somehow missed a few years ago that explains why congestion happens (Spoiler: It’s too many cars):


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Pacific Northwest News

Halftime show! This Kiro TV report has some very scary footage of a pothole-caused bike wreck on Broadway:

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6 responses to “Bike News Roundup: What causes traffic congestion?”

  1. Josh

    Regarding ‘New Seattle crosswalk noises not music to the ears of all’, it’s amusing to hear SDOT claim they have no choice but to follow MUTCD on this issue, when they’re so willing to disregard MUTCD on bicycle infrastructure on the same streets.

    (FHWA confirms that many markings in the Bicycle Master Plan Update violate MUTCD, and Seattle is already using many of them. Double-ended sharrows on greenways, sharrow marking of “crossbikes”, and sharrows with the chevrons offset for navigation directions are all contrary to MUTCD.)

    The shared lane marking means exactly one thing — a lane *shared* by cars and bikes.

    Put a sharrow on a trailhead, you’re saying the trail is shared by cars and bikes.

    Put a row of sharrows next to a crosswalk, and you’re saying both cars and bikes can drive across the road there.

    Stripe an “advisory bike lane” with sharrows, and the sharrow says cars can drive there at any time.

    Why is SDOT so eager to comply with MUTCD for pedestrians, and so casual about standards for bikes?

    1. Matthew Snyder

      Sharrows as defined in the MUTCD are basically useless. In this case, I’m glad SDOT has found a way to turn an otherwise useless road symbol into something that actually has some utility, at least in a subset of cases. I agree that SDOT is violating the MUTCD (it’s pretty unambiguous, actually), but I just don’t see the downside — do you? I find it very hard to imagine a driver seeing a sharrow at a trailhead and saying to himself, hey, this looks like a trail, but this bike symbol on the road tells me that it’s okay to drive my car there!

    2. Gordon

      Josh, while I’ll assume your criticism is in good faith, I believe you are misinformed.

      Page 810: http://mutcd.fhwa.dot.gov/pdfs/2009r1r2/mutcd2009r1r2edition.pdf

      “Section 9C.07 Shared Lane Marking
      Option:
      The Shared Lane Marking shown in Figure 9C-9 may be used to:

      A. Assist bicyclists with lateral positioning in a shared lane with on-street parallel parking in order to reduce the chance of a bicyclist’s impacting the open door of a parked vehicle,
      B. Assist bicyclists with lateral positioning in lanes that are too narrow for a motor vehicle and a bicycle to travel side by side within the same traffic lane,
      C. Alert road users of the lateral location bicyclists are likely to occupy within the traveled way,
      D. Encourage safe passing of bicyclists by motorists, and
      E. Reduce the incidence of wrong-way bicycling”

      1. Josh

        Note that all of these optional uses are for shared lanes, in compliance with the mandatory “Standard” provisions of the sharrow that define where it can be placed within a shared lane.

        FHWA has specifically and repeatedly addressed the misuse of sharrows. The double-ended sharrows on greenways have even made the FHWA FAQ for bicycle infrastructure,

        Q: Can I alter the design layout of the Shared Lane Marking (see Figure 9C-9) such as duplicating the leading chevrons on the trailing end but in the reverse direction to insinuate that bicycles are permitted to travel in both directions on the facility or lane that it is installed?
        A: No. Altering a standard marking symbol that results in an alternate meaning or potential unintended connotation is not permitted per Paragraph 1 of Section 3A.02.

        Likewise, sharrows turned or bent for navigational guidance are also in FHWA’s FAQ:

        Q: Can I alter the design layout of the Shared Lane Marking (see Figure 9C-9) such as rotating the leading chevrons to indicate advance turns for navigational direction?
        A: No. Altering a standard marking symbol that results in an alternate meaning or potential unintended connotation is not permitted per Paragraph 1 of Section 3A.02.

        On sharrows in crossbikes,specifically addressing Seattle’s use of them this way, FHWA says, “We would agree that the shared lane marking illustrated … is being used to guide and position the bicycle traffic to intentionally not use a crosswalk established for pedestrians. The marking is applied in a manner inconsistent with the provisions provided in Section 9C.07 of the MUTCD. ”

        On using sharrows to mark a bike lane through an intersection, FHWA says, “Because there is a dashed line shown to the left of the shared lane markings, this leads us to believe that a bike lane extension is being established through the intersection. This would therefore be non-compliant with Paragraph 3 of Section 9C.07 in the MUTCD. Generally speaking, if this dashed line was absent the shared lane marking can be used in an intersection if it helps assist the situation described by Item C in Paragraph 1 of Section 9C.07 if the engineer so determines. Markings that can be used to enhance the conspicuity of the bike lane extension through an intersection are the bicycle symbol, pavement word markings, arrows (not chevrons), and green colored pavement (green colored pavement is approved for statewide use in Washington State). ”

        I would agree in general that most sharrows as Seattle initially applied them are useless; they’re generally in the door zone of parked cars, and far enough right to reinforce the misperception that people on bicycles should ride on the right in lanes too narrow to share side-by-side with cars.

        The BMP Update includes new language requiring sharrows to be installed properly, centered in the effective lane, which sends a very different message to motorists.

        Having ridden streets with properly-installed sharrows, I believe they actually can improve motorist behavior by repeatedly reinforcing the safe and legal position of bicycles in lanes too narrow to share side-by-side. This is especially important for slower and less-confident cyclists, since riding too far to the right encourages the sort of hazardous motorist behavior that makes city cycling more dangerous than it needs to be.

        Most of SDOT’s poorly-placed sharrows are wearing away fairly quickly because they’re under the right tire track of motorists. With any luck, they won’t be replaced until the BMP Update is official, and the next generation of sharrows in Seattle will actually do what they’re supposed to do.

        As for sharrows on trailheads, I can say the motorists I’ve met on the I-90 Trail in the past year were both at trailheads marked as open to cars. (Sharrows are only part of that problem, of course. The trailheads also lack any “no motor vehicles” signage and many have no physical access control.) Just recently, I helped a confused driver back her car off of the I-90 Trail, she’d thought it was an alley when she drove up the trailhead — it’s wider than many paved alleys, it doesn’t have any signs saying it’s not for cars or that it’s a bike trail, etc. It was an honest mistake, but a mistake that proper markings and signs could easily prevent.

      2. Where are there sharrow markings near the I-90 trail?

      3. Josh

        At the trailhead on Hiawatha, the shared lane marking is actually on the trail itself. For quite a while there were no bollards there, either. Now there are bollards again, but the sharrow still invites cars onto the trail.

        My most recent encounter with a car on the trail was by 18th Ave S. The greenway runs to the trailhead, the bollards have been removed from the mouth of the trail, but there’s no signage or marking suggesting that cars have to stop. The trail entrance is wider than many driveways and alleys, it needs some sort of treatment that clearly says NO MOTOR VEHICLES.

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