5OYS: City will make changes to dangerous intersection in Des Moines

Local News
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DES MOINES – City council member Linda Westergaard has new information about a dangerous intersection in her district.

Local 5 On Your Side brought E 27th and Hubbell Avenue to Westergaard’s attention after a bad accident happened there a week ago. Westergaard provided an update for her constituents on Monday by posting this on Facebook:

“Engineering staff reviewed the crash data and existing signage in the vicinity of the intersection of E. 27th Street and Hubbell Avenue,” said Westergaard. “The crash data shows 12 crashes occurring at this intersection in 2014 through 2018. Based on the crash reports, five of those crashes appear to be unrelated to turning traffic at the intersection. Of those five crashes, four are not considered to be “correctable” since they were attributed to either driving under the influence, excessive speed, distracted driving or falling asleep at the wheel. The five crashes resulted in two fatalities and two possible injuries. The fatalities at this intersection were attributed to driving under the influence and excessive speed and are not considered “correctable”. Based on the number of crashes and the traffic volume on Hubbell Avenue, this intersection has a crash rate below the statewide five-year average. The statewide average crash rate for an intersection like E. 27th Street and Hubbell Avenue is 0.9 crashes per million entering vehicles or approximately four crashes per year. This intersection has a crash rate of .67 crashes/MEV, approximately 2.4 crashes per year.”

“A review of the existing signage shows that chevron signs (W1-8) and curve warning signs with speed advisory plaques (W1-1) are in place for traffic traveling south/west on Hubbell Avenue. This follows recommendations outlined in the Manual on Uniform Traffic Control Devices (MUTCD). Warning signs are not present for vehicles traveling north/east on Hubbell Avenue. A review of the advisory speed calculation for horizontal curves shows an advisory speed of 29.1 mph. This curve is currently signed with an advisory speed of 30 mph. Based on this review, staff will replace the existing south/westbound advisory plaque with a 25 mph advisory plaque and add chevrons and a curve warning sign for north/eastbound traffic,” said Westergaard in her post.

“The AASHTO Roadside Design Guide defines the clear zone as “the total roadside border area, starting at the edge of the traveled way, available for safe use by errant vehicles.” Based on the AASHTO Roadside Design Guide and the Iowa Statewide Urban Design and Specifications (SUDAS) Design Manual, a guardrail is not recommended at this location. According to the SUDAS Design Manual Table 5C-1.05, acceptable Clear Zone for Low-speed (40 mph or less Design Speed) Urban Roadways is 7 feet for an arterial roadway. The distance to the back of sidewalk from the edge of the traveled way is roughly 9 feet, and for comparison, the houses nearby are roughly 40 to 50 feet off the Hubbell Avenue traveled way. Driveways along the corridor also prevent the ability to even put a continuous guardrail along Hubbell Avenue,” wrote Westergaard.

Streetlighting was reviewed along the corridor and street lighting is consistent with the City’s standard placement. A request has been placed with MidAmerican Energy to verify that all lighting is operational on Hubbell Avenue between E 29th Street and Guthrie Avenue.

“Due to the traffic volumes, speed limit, and functional classification of Hubbell Avenue, changes to roadway geometrics would be necessary in order to effectively reduce speeds. This could include narrowing the roadway and/or reducing the number of lanes through pavement marking changes. A full corridor study would be necessary to review the benefits and challenges in making changes to the current roadway geometrics. However, my understanding is several years ago (before I moved to Des Moines) the City re-striped Hubbell Avenue in this area, converting the 4-lane cross section to a 3-lane cross section (a method recognized by the U.S. Department of Transportation Federal Highway Administration as a “Proven Safety Countermeasure” which can improve safety, calm traffic, provide better mobility and access for all road users), and area residents advocated to put the cross section back to 4-lane cross section,” Westergaard said in her post.

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