Yesterday featured a quick write-up on advisory bicycle lanes, with a bit of discussion on what they are and where they could possibly go in Minneapolis. The rationale behind the advisory bike lane is to stripe a bicycle lane on narrow, low-traffic streets, with vehicles using the remaining center space and merging into the bike lane when needed to pass opposing vehicles, yielding right-of-way to bicycles in the process.
One of the key features of a street featuring advisory bike lanes, and a feature that makes the concept possible, is the lack of a yellow centerline stripe that would normally divide street traffic into its opposing directions. The Federal Highway Administration’s Manual on Uniform Traffic Control Devices (MUTCD) sets down the criteria by which a street centerline is needed or not needed. In short, the MUTCD (which has legal teeth via Federal law) requires a centerline on urban streets at least 20′ wide and with an average daily traffic (ADT) level of 6,000 vehicles or more. The MUTCD recommends (but does not require) centerlines if that daily traffic level is 4,000 vehicles or more.
Minneapolis Street Centerline Requirements, using MnDOT traffic data. Map by the author.
This map, using the latest (mostly 2012) MnDOT traffic data, is color-coded to show where street centerlines are required, recommended, or not required. Red streets have traffic volumes (at/above 6,000) that require a centerline and thus are ineligible to receive advisory bike lanes. Yellow streets are in the traffic volume range where a centerline is recommended, but not required. Green streets have daily traffic volumes below 4,000 and thus do not require a centerline. Conversely, they are potentially good candidates to receive advisory bike lanes. White streets are neighborhood streets that likely do not have high traffic volumes and would also be good candidates.
As you can see, there are several streets that could potentially be converted to include advisory bike lanes. In southwest Minneapolis, the combination of W 60th St, Sunrise Dr, and W 58th St is a potential candidate except in the immediate vicinity of Lyndale Ave. Long stretches of 4th Ave S, Bryant Ave S (already a Bike Boulevard), and Dupont Ave S could be converted. In far northwestern Minneapolis, Humboldt Ave N, Bryant Ave N, and 51st Ave N are possible streets for conversion. In Northeast, there are several streets in the area bounded by Central Ave, University Ave, and Lowry Ave that could be converted. There are also several possible conversion streets in the area between Hiawatha Ave and the Mississippi River.
Are there any recommendations on upper limits for sharrows, Froggie? The highest-volume street I’ve seen them on is Washington Ave downtown, although they seem thoroughly faded by now.
Also: although I have not seen it implemented yet in Minnesota, there is a theoretical option of doing an advisory lane as part of a multi-lane facility. So you might have a four-lane street with the right 1/2 of the outer lane being an advisory bike lane. I believe this is shown in the documents of recommendations for bike improvements on Snelling north of Pierce Butler Rte. Is traffic volume an issue here?
I’m not aware of any upper traffic limit for sharrows, but I liken that situation to what Walker mentions regarding advisory lanes: at some point, vehicle traffic is enough to where bikes should really have a dedicated facility (bike lane, cycletrack, separate path, etc etc).
Wouldn’t that be true, except in cases where it’s really alright for vehicle traffic to match bicycle speeds (15 MPH?)
Yes, I think so. Though volume would still matter, however if the speed limit is 15 mph, cars aren’t allowed to pass bicycle riders, etc, I’d guess the volume will then naturally be quite low?
15′ wide is a requirement for sharrows (wide outside lanes) and under 35 mph speeds, and moving the route to an alternate street occurs with 10,000 AADT, avg speeds over 30 mph. (Page 121 of MnDOT bike facilities design guide)
Interesting. If we have 15′ min for sharrows, why not just do a 10′ lane and 5′ bike lane? It also makes me wonder why we are letting AADT and average speed dictate our street design, when our street design should be dictating speed and volume.
Where did you get that sharrow info from? According to the current MnMUTCD, the only requirement for a sharrow is (9C.7):
> Shared Lane Markings shall not be used on shoulders or in designated bicycle lanes.
The Guidance (in addition to recommending placement only on ≤35 mph roads) goes on to specifically anticipate lanes that are less than 15′ wide:
> If used in a shared lane with on-street parallel parking, Shared Lane Markings should be placed so that the centers of the markings are at least 11 feet from the face of the curb, or from the edge of the pavement where there is no curb. If used on a street without on-street parking that has an outside travel lane that is less than 14 feet wide, the centers of the Shared Lane Markings should be at least 4 feet from the face of the curb, or from the edge of the pavement where there is no curb.
It has been an ongoing source of confusion that the MnDOT state-Aid Standards as well as the design guide use the term “shared lane”, which sounds very similar to the term “shared lane markings”. Similar enough that many engineers I know pretty much equate the two (as well as the term “Wide Outside Lane”). I think this is erroneous. However, I know plenty of traffic engineers who use this guidance to determine where shared lane markings will or will not be used, despite the fact that this guidance existed before shared lane markings were even added to the MUTCD, so they clearly are not referencing the same thing.
Personally, I think using sharrows in wide outside lanes actually creates a lot of confusion, since they’re generally placed at about the right tire track. Even in a wide lane, that doesn’t generally leave enough room for a motorist to make a legal pass in-lane. I prefer them centered in narrower lanes, where it’s clear to a motorist that they must change lanes to pass.
Conceivably a sharrow at the extreme right of a 15′ lane might be workable. But then again, so would a 10′ and 5′ bike lane adjacent to each other.
We could always design streets in a way that discourages traffic, thereby lowering the counts. It seems like the ultimate mistake to think that we need to accommodate the number of vehicles observed, in the current scenario, during a two day study. Maybe if we narrow the effective street width for cars, and slow cars down, we will end up with fewer cars on that street.
And what would happen if we “violated federal law” and removed centerlines in violation of MUTCD? I’d say it’s worth a fight.
Agree with discouraging (non-local?) traffic. I would think the best way to accomplish this is make the route a non-thru route for motor vehicles. Opposing one-ways?
I’m not sure there’s a need to violate MUTCD, at least for advisory lanes, since I’d guess that the volumes that recommend or require centerlines are likely also volumes that would be too great for advisory lanes.
Those thick red lines — where there are high car traffic volumes and, not coincidentally, where many of the most useful destinations lie — would be a pretty great protected bikeway network….
Yes
True, and in many neighborhoods there is low demand for on-street parking on these busy streets outside of the commercial nodes. Many people, including myself, are more comfortable riding on advisory lanes rather than crammed 10/5/7 configurations. This is especially true on east-west streets in Mpls, with tight intersection spacing. But those are also the streets which have lower on-street parking demand due to significantly less building frontage in most spots.
Sacrifice parking on one side, and there are many options. 10′ lanes, a single 9′ parking lane (moving the worst of the door zone to within the parking lane), and then 6+ foot bike lanes on each side. This is similar to how 42nd St was painted east of Cedar Ave a couple years ago (although rarely repainted, never signed well, and never enforced on parking).
The only problem is when it tightens at business nodes, where parking demand is much higher, space for turn lanes and bus stops are needed. It’s much more likely that bike lanes will become a short stretch of sharrows. But that shouldn’t be done lightly. If that’s done, it should include gateway-style calming demarcating the end of the node (and the change in lane configuration) possibly including features like a small median or chicanes.
fyi, 42nd was repainted recently. The goofy thing about that is the curves painted at two uncontrolled intersections where they painted crosswalks. I think it makes cars think they don’t have to stop for pedestrians at any of the other intersections. Also, it makes the bike lane mysteriously “merge” into the traffic lane (or vice versa) periodically.
Further east on 42nd (between 28th and Hiawatha) they’ve extended the painting in the way you suggest (parking on one side only) which is a big improvement, imho.
“Also, it makes the bike lane mysteriously “merge” into the traffic lane (or vice versa) periodically.” Sounds like a how can we best get rid of as many bicycle riders as possible.