January 2


Neighborhood Traffic Calming Experiment

Traffic Corner Tuesday, brought to you by Spack Enterprise and its family of transportation-related companies, completed its latest webinar just over a week ago. Traffic Corner Tuesday is our monthly webinar presenting research, case studies, and interesting discussions on our favorite topic – transportation. For those who missed it, here’s a summary of that webinar along with a link to the webinar if you want to watch it (it’s short, about a half hour of content followed by a Q&A session). You can also sign up for our next Traffic Corner Tuesday here.

As with most cities, the City of St. Louis Park in Minnesota has a Pavement Management Program to proactively address the conditions of its residential streets. As part of this work, the City’s city council directed city staff to look at all aspects of the neighborhood livability and “living streets” considerations as a part of their transportation projects. This review includes the streets, utilities, fiber, sidewalk network, stormwater runoff, traffic management, and tree preservation.

For the Elmwood neighborhood, city staff recognized the need for potential changes to the roadway network and began exploring options before the maintenance program work. They partnered with Spack Consulting in 2017 to explore the existing neighborhood network, develop improvements, and determine the impacts of these changes.

Working with the City, we first determined the goals of the project, which included:

  1. Close the Aldersgate cut-thru, an unfortunate result of previous changes that left a private parking lot as a connection between two roads. This cut-thru route was clearly an issue as lots of drivers traveled through the parking lot as a shortcut into the neighborhood.
  2. Engage the neighborhood, ensuring the process is transparent and residents have the opportunity for input and reviews.
  3. Reduce neighborhood road 85th percentile speeds to 30 mph or less if possible (Jargon – 85th percentile is the speed at which 85 percent of the drivers are at or below and is a standard measurement that can set the posted speed limit). In particular, examine potential ways to slow drivers if they are going faster than the posted speed.
  4. Reduce the heavy trucks on residential roads and focus that truck traffic on the collector roads.
  5. Keep the Average Daily Traffic (ADT) at about 1,000 vehicles per day or less. This level of traffic is well below the actual capacity of a two-lane road, but has been identified as a ‘livability’ issue. Any changes should balance traffic on the local roads and keep traffic at or below that threshold.

Working with city staff, we developed a process designed to explore options and meet the identified goals. The summary of this process is:

  • Team Meeting
  • Neighborhood Charette
  • Data Collection – Obtained volume, speed, and classification counts at 58 blocks and four intersections to provide a benchmark before making any changes.
  • Model and Create a Draft Plan – Using the data collected, we determine potential changes and what those changes might mean to the area traffic.
  • Explanation Neighborhood Meeting – Present, listen (which is really important), and adjust the plan based on the neighborhood discussions.
  • Experiment – Used barrels, delineators, and temporary signs to create the proposed plan on a temporary basis. We then collected data in the same manner as the benchmark at two separate times.
  • Analyze – With the benchmark data and two sets of experiment data, we determine the changes, how closely it matched our expectations, and developed graphics, charts, and tables to explain the results to city staff.
  • Finalize Plan – Use the results to help us focus on changes that made a difference and those that had no impact or did not provide the result desired. For this project, about 3/4 of the proposed changes made it into the final plan.
  • Neighborhood Wrap-up Meeting – Present the results and final plan to the residents, answering additional questions or concerns about moving forward.
  • Council Approval
  • Design and Build it

Here’s a graphic showing an example of graphics we prepared for the residential meetings. As you can see, we presented the locations of the proposed changes, how we would set-up a temporary version for testing, and what the final version could look like if fully implemented in the end.

Here are the five key lessons learned from this process:

  1. This process and experimentation is a great method to provide an easier path for Council approval.
  2. The Neighborhood Charette (design meeting) unearthed resident concerns and ideas we may not have found without them. Truly listen to what they say and adjust your plan as needed.
  3. Barrels alleviated the initial fear of change since it’s just an experiment that can be easily removed if things don’t work. It’s not a permanent change.
  4. An experiment can fine-tune your plan and make it better. We only implemented about 75% of the initial plan; the other 25% was not needed based on the data.
  5. Use Third Party Facilitators in your meetings. The engineers can then focus on presenting, listening, and discussing rather than enforcing the rules of being respectful.

Following our presentation in the webinar, we had a great discussion with attendees which lasted almost as long as the presentation itself. Here’s a sample of the many questions and answers related to the traffic calming experiment.

  • How long from the team meeting to the council approval?
    • Took about nine months
  • At what point in the project did you decide to do this experiment?
    • Early at the team meeting stage, came up with that strategy to alleviate fears in the neighborhood
  • You said you set up traffic tubes to count the vehicles in the area, how did it take for you to get the data that way?
    • Weeks’ worth of effort, setting up each tube counter takes about 15 minutes and we had almost 60 tube counters for each phase, and then we set up some video cameras to do turning movement counts for a couple of days, so we could do the compacity analysis, and check on the pedestrians and bicycling traffic through those areas, heavy data project
  • How often did the temporality barrels and tubes need to be fixed? From being moved or changed by drivers or residents during the temporary data collection?
    • As far as we know, wasn’t that much because of the nature of the area – low speed with regular drivers who knew the roads and the changes. Some of the traffic circles did need to be adjusted based on traffic patterns.
  • What role did winter maintenance play in considering changes, for example, are there concerns about having traffic circles in the middle of the road when snow removal was needed?
    • No, the City is committed to making the changes work. The experiment phase ran in fall, summer, and spring without dealing with snow. The public works and engineering staff discussed the types of treatments suggested and agreed they would be OK with the maintenance work.
  • Who funded the project and was there issues associated with the funding or finding the source for the funding?
    • From my understanding, it came from general city funds part of the general engineering budget overall. Neighborhood reconstruct project the city had the funds available and were able to make it happen.
  • What were the total cost of the project and a study of this magnitude?
    • Order of magnitude for our assistance and data collection was under $50,000. The City’s work is not included in that sum.
  • How do you address any neighborhood concerns unearthed at the workshop sessions that could be solved with the 3/4 change?
    • We were upfront about them, what we could do and what we couldn’t do. Some of the big changes in the neighborhood included adding more sidewalks which resulted in the loss of some trees. All these changes are compromises, and we were honest about the good and the bad, along with why we thought the good outweighed the bad.
  • Did you collect pedestrian crossing information and how did this play into your study if you did?
    • In certain locations yes. The pedestrian volumes became one more factor we considered as we determined potential changes.
  • Were there any issues brought to you guys regarding the residents being confused by the barrels for the traffic circle?
    • No, although our data collection guys did have a lot of contact with the residents while they were out there, there was a lot of communication, and that slowed them down, but they were respectful and listened to the process

This webinar turned into a great discussion and back-and-forth about our process, the results, and advice for similar situations. We encourage you to listen for yourself and, of course, join us for our next webinar coming soon.

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Mike Spack

My mission is to help traffic engineers, transportation planners, and other transportation professionals improve our world.

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