Wednesday, March 30, 2011

Bike Lanes on the Lowry Bridge


Post by the Hawthorne Hawkman, images from the Lowry Avenue Bridge website.

One of the bright spots (of which there are many) on the redesigned Lowry Avenue is the ample space provided for bike lanes.  Last week some cyclists and I had a very wonkish discussion about how those lanes would be incorporated into the shiny new Lowry Bridge.  If you'll notice from the design specs above, there don't seem to be any marked bike lanes.  If the bridge is built exactly like this, I see three possible prospects, all of them unappealing in their own right:  bicyclists will have to share the road with high-speed traffic, bikers will share the walkways with pedestrian traffic, or bikers will be required to get off of their bikes and walk with pedestrians if they're not willing to brave traffic conditions.

In an email exchange with some cycling activists and staff from County Commissioner Mark Stenglein's office, it's unclear how bicycling will be supported on the bridge.  A biker claims there will be no marked lanes while a staffer says there will be two 11-foot lanes of traffic and two 4-foot marked bike lanes in each direction.  For the record, the Minneapolis Bicycle Master Plan, passed in 2001, calls for the entirety of Lowry Avenue to have bike lanes.  Readers of both this blog and the Irving Inquisition will know how much I want to see the Lowry Bridge adhere to master plans.

With the formal public comment period over and done, and construction underway, changing the actual width of the bridge is out of the question.  But if the lane configuration needs to be tweaked, perhaps that can be done.  For instance, I'm told that...

...the average daily traffic on the Lowry Bridge in 2007 was 13,800 eastbound and 15,800 westbound.  What?  Did two thousand people a day come to north Minneapolis and never return?  If so, how come our census numbers for the senate district went down by 9,000?  More likely, I suppose, is that they drove over the slippery metal grate that passed for a roadway, said "Oh, HELL no," and went back home using a different route.  At any rate, the daily traffic on Lowry before was pretty easily handled by two lanes of traffic, with turning lanes at each end.  The density certainly isn't there right now for a need to go to four lanes, so maybe we ought to keep the same lane configuration for the time being and have more widely marked bike lanes.

After all, the MnDOT Bikeway Facility Design Manual suggests 6-foot bike lanes on urban roads with speed limits and traffic loads similar to Lowry.  Strict adherence to that guideline would probably crimp traffic too much on the bridge, but cutting down lane widths slightly to add 5-foot lanes would make the bridge more bike-friendly.  The County may resist cutting lanes down to 10.5 feet.  But a study by the National Cooperative Highway Research Program showed no significant difference in crash rates for urban arterial roads such as Lowry when lane widths were 10, 11, or 12 feet.

I expect that at the very least, we'll see marked bike lanes along the bridge, as well as clearly marked instructions for cyclists approaching the bridge.  But Minneapolis shouldn't expect to keep its title as the #1 biking city in America by doing just the bare minimum for our cyclists.  We've only got one shot at building this bridge, so let's not hold back on what it can provide for our city.

9 comments:

  1. Jeff, coming home last night about 9pm, I saw Pappy's was NOW OPEN, according to the no less than 4 neon yellow and pink signs displayed up and down both sidewalks. And the common neon OPEN sign in the window.

    If anyone is interested in eating their, look on your Cub Foods receipt for a coupon. Jeff, you can have mine if you like.

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  2. Jeff, I would double check that information you've received from the County staffer. Given my experience as a traffic engineer (having worked with Hennepin County on numerous occasions), I can tell you that it would be highly unusual for them to mark 4' bike lanes. The Hennepin County Bike Design Guidelines recommend a minimum of 6'. And even though the County design guidelines are almost universally regarded as outdated (including by many at Hennepin County), I have never seen the County back down from these standards to mark on-street bike facilities that don't meet the minimum specs (and certainly not to mark bike lanes as narrow as 4'.

    The project web site doesn't have very much useful information, but it does have this presentation, which includes a poor-quality image from a signed plan set. The plan set is hard to read but it looks like it's marked "13' lane, 15' shoulder.

    This is both good news and bad news for cyclists. The good news is that it seems to imply that the county plans to stripe only one 13'vehicle lane in each direction to begin with (which is probably an 11' lane + 2' "clear zone" between the left side of the lane and the center median), leaving an extraordinary 15' on the edge of the roadway to do whatever else they want to (which may include a marked bike lane (hopefully wider than 4')).

    The bad news is that these dimensions seem to imply that on-street bike lanes are not part of the long-term plan for the bridge. Long term, we can guess that the 15' shoulder will eventually be re-striped as an 11' lane and a 4' "clear zone" between the right edge of the lane and the sidewalk. This seems to be in-line with the info you received from the staffer. This "clear zone" is required if State-Aid dollars are being used to pay for a portion of the project (which I suspect is the case). These clear zones can look a lot like bike lanes, and they are often mistaken for them (especially by a non-techical non-engineer staffer just looking at a plan set). What's more, on the ground, they are even easier to be mistaken as bike lanes by drivers and even cyclists. In fact, the only real difference between a 4' "clear zone" and a bike lane is that a bike lane must be 5' wide (or 6' in Hennepin County). However, they are not bike lanes, and the county does not have a history of marking these "clear zones" as bike lanes. They don't get marked with bike lane pavement markings or signs, and things like gutter pans or storm drains are not designed to be bike friendly.

    That being said, it would also be highly unusual for the County to propose to stripe bike lanes on the bridge today if they couldn't guarantee they would be there indefinitely. They generally prefer not to stripe it at all than to stripe it today while planning to remove it later.

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  3. It's nine and a half feet across the mirrors of a big truck, and the Lowry bridge has always seen plenty of them. Thus twelve feet is the minimum safe lane width.

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  4. Nomi P,

    I think you mean "there" and not "their". Their is a possessive pronoun.

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  5. Ugh. Typo. The sentence towards the end needed to read "Minneapolis SHOULDN'T expect to keep its title..." which is what I have changed it to.

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  6. It will be great to ride the full length of Lowry up to the Grand Rounds again. I know riding down hill from Theo Wirth to Northeast was EXCELLENT during the period when the bike path was completed and the bridge was still up.

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  7. It's not true that bikes will have no place to go. You didn't mention the super wide sidewalks that will be on the bridge. The "sidewalks" on the bridge will be 12 feet wide and are intended to be multimodal paths for cyclists and pedestrians, so cyclists will feel welcome on the new bridge :) More experienced cyclists can still use the road if the shared use path isn't fast enough for them, but there will not be on-road bike lanes.

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  8. FYI - the Minneapolis Bicycle Coalition is reporting that the plans may have changed recently to allow on-street bike lanes.

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  9. @Reuben, that's both encouraging and a little intriguing. I was at an Above the Falls Advisory Committee meeting last night and the people in the know there were saying that bike lanes were in danger of being eliminated due to cost constraints. Cost constraints are also allegedly threatening the way the ATF plan calls for north/south bike connections at the foot of the bridge.

    I hope the article you posted is more accurate.

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