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Converted Traffic Flow Supports Corridor Mobility Goals: Downtown Des Moines

Mobility Plan Strives to Create a Safer Downtown by Targeting One-Way Streets

SimTraffic 10 PM Peak Queuing Results

In the City of Des Moines’ continuing effort to improve their downtown region, Snyder & Associates was tasked with completing a traffic analysis and concept layout for the 5th Avenue corridor extending from Cherry Street to Grand Avenue. The layout was guided by the principles outlined in the city’s “Connect Downtown” Mobility Plan. This targeted plan’s goal is to make the downtown safer for pedestrians, bicyclists, and drivers alike by implementing several solutions. Among those solutions are minimizing the number of one-way streets to encourage slower speeds, modifying both the number and size of driving lanes to accommodate more on-street parking or dedicated bicycle lanes, and giving careful consideration to left turn lanes in order to prioritize pedestrian safety.

Traffic Flow Issues along the Downtown Corridor

Several unique traffic flow situations needed to be addressed to improve the 5th Avenue corridor, including:

  • The closely spaced intersections between Cherry and Mulberry Street presented potential queuing issues if converted to two-way access from the current one-way designation
  • Misaligned crosswalks at the Locust and Walnut Street intersections created a confusing and unsafe situation for pedestrians
  • Poorly aligned bicycle lanes discourage bicycle traffic along the length of the studied corridor

Converted Traffic Flow for a More Successful & Vibrant Downtown

The concept layout created by Snyder & Associates provided many solutions that would simply require changes to pavement markings in order to implement. Better marked bicycle lanes and realigned crosswalks are just two examples. The recommended physical improvements were minimal and mainly consisted of modifying the median between Cherry Street and Court Avenue for improved traffic alignment and pedestrian safety, the relocation of several signal poles, and the addition of curb bump outs near designated intersections. Bump outs help to increase pedestrian visibility and shorten the crossing distance at crosswalks. Best of all, the conceptualization project affirmed that converting 5th Avenue to two-way traffic between Grand Avenue and Cherry Street would maintain a similar level of operation as the existing one-way corridor. While the left turn lane for southbound traffic at Court Avenue would need to remain to avoid queuing issues, it was determined this would not interfere with the overall mobility goals of the corridor. The result of these proposed improvements mark another step taken toward fulfilling the city’s long-term “Connect Downtown” plan.

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City of Des Moines

Client Type

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Mark Perington, P.E., PTOE

Mark Perington, P.E., PTOE

Traffic Work Group Leader

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