Washington Avenue, Remodeled

Source - Downtown 2025 Plan. This specific rendition probably wont happen, since it blocks all access to I-35W. Good imagination, though.

Source – Downtown 2025 Plan. This specific rendition probably wont happen, since it blocks all access to I-35W. Good imagination, though.

Over the past year or so, it seems a roadway redesign war has evolved over Washington Avenue in downtown Minneapolis. Luckily, it seems like the so-called war was won by urbanists.

A couple weeks ago, the Hennepin County Board voted in favor for a much more livable Washington Avenue design on a split 4-3 decision. The new 3A design between Hennepin Avenue and 5th Street Southwill have two through lanes in each direction, along with separated right and left turn lanes at appropriate intersections. The corridor will also feature protected bike infrastructure on each side, as well as expanded sidewalk space.

Source - Hennepin County

Source – Hennepin County

Although this scenario is arguably the best option that could have been chosen for the historically tortured corridor, I couldn’t help but think what the outcome would be if the Hennepin County chair members swayed one vote the other direction.

To their credit, it was likely that many referred strictly to the model numbers and figures found in the Operation Analysis document, completed in late April earlier this year, and felt worried that a redesign with smaller lanes would spell a traffic disaster. The report, a very well done but bone-crushingly technical 73-page epic, analyzes current and future traffic projections along the entire Washington corridor from Hennepin Avenue to Interstate 35W. The report spells out potential scenarios for redesign, and takes into consideration many outcomes based around the attempt to predict to-the-minute behavior 25 years in the future.

The report is well done according to traditional traffic engineering standards, followed all recommendations that Hennepin County provided, and abided to all under-spoken standards that encapsulate an analysis like this. The problem is, the “traditional” traffic engineering method is a relic of the past, when all that was seen was automobiles – automobiles everywhere.

I took it upon myself to investigate what the outcome of the analysis would be if two main assumptions were changed.

First, the 0.5% annual growth rate for traffic that Hennepin County recommends matches early-1990s trends at best. This also follows a nationwide tradition of predicting traffic very wrong. To change this, I used a 0.2% annual growth rate based on an old Metro Transit comprehensive plan completed by Mark Filipi. In my opinion, the 0.2% rate is also conservative, but to restrain the urbanist within me for the exercise, I found it to be a reasonable number in the analysis. And who knows, maybe some people will drive more than current trends in the next two decades.

Source - DC Streetsblog. Okay, we get it... people are driving less. Sheesh.

Source – DC Streetsblog. Okay, we get it… people are driving less. Sheesh.

Second, instead of using the seemingly massaged traffic counts seen in the report, I used City of Minneapolis numbers directly from their traffic management database. It was previously found that the AM peak period counts in the report were 10% – 35% higher than those in the traffic database. In a similar fashion, the PM peak period counts were 8% – 46% higher than those in the traffic database. Reason? It is a common traffic engineering standard to round counts up.

To analyze the traffic, I used software called Synchro, which is commonly listed as a go-to analysis tool by many traffic engineers. To use and analyze data with Synchro, I designed the Washington Avenue corridor from 1st Avenue North to Portland Avenue South with appropriate lanes and block length dimensions. According to the report, the PM peak period is the critical design time span, so I applied those counts to the corridor for this exercise.

Example of Synchro used in one scenario. Its like real world SimCity, but with way more numbers.

Example of Synchro used in one scenario. Its like real world SimCity, but with way more numbers.

I created several potential redesign scenarios for my full report, but to cut to the chase (you’re welcome), the most important finding in future projections was that the layouts recommended in the report were potentially over-designed – meaning that vehicle lane capacity was higher than it needs to be in the year 2035. Although this seems like a no-brainer considering the notion that more projected vehicles cause more projected congestion, it is an important finding.

After the scenarios were created, one stuck out of the bunch like a rollover truck blocking a freeway lane. This projected future scenario, set for the year 2035, lists a 4-lane Washington Avenue design with some protected left turn lanes but zero protected right turn lanes. The scenario also assumes a 10% reduction in PM traffic due to the new northbound Interstate 35W onramp at 3rd and 4th Avenues that will likely relieve congestion in the downtown grid. Long story short, the report found this scenario to be ineffective, and still recommended protected right turn lanes throughout Washington. Using my analysis, however, the zero right turn scenario allowed projected traffic to move at a Level of Service of C or higher at all intersections, which is usually sought by traffic engineers during a redesign project.

Data

Note the Level of Service (LOS) values for each intersection. In the remodeled case, all intersections perform at a LOS of C or higher.

So, what does this all mean? Well, at this point in time for this specific project, a big pile of nothing goodness. As stated before, the Hennepin County board approved the design for six blocks of Washington with four lanes, and the City of Minneapolis will likely approve of the design in March. However, there are some important things to consider:

  • Why do so many traffic engineers still insist on using annual projection traffic values that severely overestimate true demand for a corridor? Well, much of it likely retreats to the classic notion of “We’ve always done it this way” and “We are following traffic standards”. This mentality must change in the traditional traffic engineering field to accommodate 21st century transportation trends, especially in downtown areas like Minneapolis where so many transit and non-motorized projects are located.
  • Why do we predict estimated intersection delay for vehicles to the nearest second, while planning for a corridor design 25 years into the future? This mentality probably worked in the so-called golden age of highway design, but should change to match probable future technology implementation. In 2035, will we see large-scale autonomous vehicle deployment? In 2035, will we see a larger urban population base that chooses to walk, bike, or take transit on a regular basis?
  • The Hennepin County Board approved this on a 4-3 split vote. If one board member felt especially punchy that day and decided to vote the other way, Washington Avenue may have ended up as a STROAD like its current form, which would be disastrous for the neighborhood. Again, this begs the question… Why does Hennepin County have to control a corridor that should be an exclusive Minneapolis problem?
  • Seriously, what is with the obsession with protected right turn lanes? I understand that they help with intersection delay, but really do not impact it much. These right turn lanes may end up affecting the cycle track design – lets hope a good bikeway design is implemented along Washington.

Of course, my “more-of-a-thought-experiment analysis” is a nice example of  bad engineering, as I ignored any traffic count rounding standards and balances. I also did not design Washington past 5th Street South, and instead focused efforts on the corridor that will be reconstructed in 2015. There are also many unlisted notions that are often used in analysis, including the use of multiple software programs aside from Synchro to double-check intersection performance. Take my values and analysis with a large, boulder-sized grain of salt.

Still, it is interesting to see that altered traffic assumptions, including lower projected traffic growth values, impact corridor performance that significantly. I believe engineers should carry apply this idea toward future redesign projects, especially those located in urban corridors; this sorta-study sorta proves it.

(If you wish to see a copy of my full report, you can comment below and I can send you one… if I am feeling nice.)

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17 Responses to Washington Avenue, Remodeled

  1. Alex B. January 8, 2014 at 8:22 am #

    Excellent point about the precision assumed in this kind of analysis: down to the second, 25 years in the future, based on untested assumptions.

    So much of our analysis is pseudoscience. And that’s fine, so long as we discount it for what it is. The expression of the values we want and the kinds of places we want to build are far more important in shaping how a street will get used.

  2. helsinki January 8, 2014 at 10:02 am #

    You write: “the Hennepin County board approved the design for six blocks of Washington with four lanes”.

    Yet the 3A proposed layout plan clearly indicates a third westbound ‘thru’ lane (is ‘through’ really so much longer to spell?). Has this lane been removed?

    Assuming not, with the addition of the left turn lane the new design therefore has six lanes (two eastbound, three westbound, one median turn lane).

    Considering how the existing design has 7 lanes, this hardly seems radical.

    • Chris Iverson
      Chris Iverson January 8, 2014 at 10:14 am #

      The third through lane in each direction has been removed in the final design in place of longer turning (both left and right) lanes. My apologies for the misunderstanding – the full design posted in that picture was indeed a six-lane proposal, but is outdated. I was more focused on illustrating the cycle track, sidewalk and transit space in the right image. The layout for both elements should remain unchanged.

      • helsinki January 8, 2014 at 10:36 am #

        Thanks for the clarification. Do we know how long the right turn lanes will be?

  3. Alex January 8, 2014 at 11:06 am #

    But if they got rid of the protected right turn lanes, where would they put the bus stops?

  4. spiderleggreen January 8, 2014 at 11:48 am #

    Maybe the county could offer these engineers some early retirement options? And move their offices from Medina, to somewhere where there are more people than cows!

  5. hokan January 8, 2014 at 12:35 pm #

    Protected right turn lanes will be essential to protect cycletrack users.

    Drivers place the vast majority of their attention to the front. Makes sense because that’s where most of the dangers lie. Intersections are especially hazardous; that’s where most crashes happen. Without protected right turn lanes we’re asking motor vehicle drivers to look over their shoulder as they approach dangers (intersections). That’s going to fail.

    Protected right turn lanes will greatly reduce the threat to people using the cycletrack.

    • Chris Iverson
      Chris Iverson January 8, 2014 at 2:01 pm #

      I’m not disagreeing with you, but don’t drivers have to do that for regular on-street bike lanes now? High traffic corners like 10th Ave SE and University do have right turn lanes that manipulate bike movements, which certainly helps. However, most intersections don’t, and create pseudo-RT lanes with dotted paint bike lane. Assuming they approach faster, drivers would still have to yield to bicyclists.

      Since this design has the protected bike lane right next to the road without a tree-lined barrier, it should in theory give drivers the same up-front awareness as a normal bike lane would. The advantage for the protected cycle track is clear, but I still lean towards the notion that the right turn lanes only promote faster vehicle speeds, which would cause more safety concerns in the long run.

      • hokan January 8, 2014 at 2:42 pm #

        With regular on-road bike lanes, drivers must prepare for a right turn by moving as far to the right as practicable , including changing lanes into the bike lane. This lane change should happen early — 100-200 feet before the intersection — before the driver needs to negotiate the hazards at the intersection.

        Ref: Traffic Regulations, Minnesota Statute 169 Section 19.

        • Janne January 8, 2014 at 9:30 pm #

          Suppoedly. But just ’cause it’s the law, it’s not like they DO. Try riding in a bike lane downtown sometime. Anytime. Especially rush hour.

          • Chris Iverson
            Chris Iverson January 9, 2014 at 9:19 am #

            I have to agree with Janne here. Just because it is law doesn’t mean drivers follow it, and police enforce it too. This is especially true in the erratic downtown grid. In my eyes, I still see the RT lane as added space for vehicles to move that would otherwise move parallel to through traffic. Anything that increases the “efficiency” of vehicular traffic on turning movements is more of a safety hazard in my mind. On the other hand, I can certainly see the justification for LT lanes if only because they would have protected stoplight phases.

  6. Jim January 8, 2014 at 5:02 pm #

    Nice work. It’s unfortunate that someone with traffic modeling software and a relatively small set of data can undress both the county engineers and the consultants they pay in an unpaid blog post. You’re clear that there are some fuzzy edges, but that’s precisely the point, getting this close the the truth is ridiculous based on the level of effort. Thanks for the stroad shout out, would love to get you in the loop on the transportation stuff on the docket at ST.

    • Chris Iverson
      Chris Iverson January 9, 2014 at 9:13 am #

      Thanks for the comment! I certainly did not mean to undermine the efforts of the engineers themselves, but moreso the way these types of studies are conducted, and the conservative nature of these processes. The lesson I’ve picked up recently is that its hard to change tradition when something is decades old and worked for that long. This was actually part of a term paper for a class, so it did take me a fairly substantial amount of time to complete, as far as effort goes.

      • Sam Newberg
        Sam Newberg (Joe Urban) January 9, 2014 at 10:07 am #

        Undermine away! In the book Desert Solitaire, Edward Abbey described an argument he had over a road “improvement” proposed for Arches National Park (then a Monument). The engineer implored “you need this road.” Abbey went on, “he was a pleasant-mannered, soft-spoken civil engineer with an unquestioning dedication to his work. A very dangerous man.”

        Traffic engineers need to be questioned at every turn (pun intended).

  7. Kari Sinkko January 8, 2014 at 6:29 pm #

    As far as I’m aware, setting long distance goals is to ensure that we don’t end up with plans that fail in the short term and provide a visioning exercise that sets an agenda, so 25 years is a long time, but it’s a historical method. As for your modelling, it’s quite impressive that we can do such things the imitate the uses based on assumptions, but as others and yourself have pointed out, it’s not necessarily going to be correct, but something is better than having nothing. I guess it’s also a matter of being able to evaluate the current trends than to just use the past as a template for the future.

    • Scott Engel January 8, 2014 at 11:31 pm #

      Thanks Chris for your analysis of the traffic study.

      I have to disagree, however, that the design is a huge improvement for all users. The sidewalks will not be much wider than today- especially at the major intersections like Hennepin and 3rd Avenues. Crossings at those locations for pedestrians will remain similar to today- 6 lanes of traffic + 2 bike lanes.

      It’s too bad that the 6th (right turn) lanes based on guesswork about traffic levels during ONE of of the day 25 years from now.

      Scott Engel
      Mpls Pedestrian Advisory Committee
      12th Ward Member

  8. Sam Newberg
    Sam Newberg (Joe Urban) January 9, 2014 at 9:55 am #

    Andres Duany, a founder of the new urbanism, was recently quoted on Twitter as saying effectively “you cannot control congestion, but you can control how many lanes you build.”

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