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HomeMy WebLinkAboutCity Council Memo 7th Avenue - 2017 October 17, 2017 Resolution authorizing the installation of radar feedback signs on Seventh Avenue, between Court Street and Glendale Road. Prepared By: Sarah Walz, Assistant Transportation Planner Reviewed By: Kent Ralston Fiscal Impact: CIP#S3816 Recommendations: Staff: Approval Commission: N/A Attachments: None Executive Summary: The residents of Seventh Avenue, between Court Street and Glendale Road, successfully completed the City of Iowa City’s Traffic Calming Program. A traffic study dete rmined that the street qualified for the program based on traffic speeds. In 2016, staff recommended against a request to install speed humps along this section of street based on the concerns expressed by the Fire Department. Staff reconsidered options along the roadway and are now proposing a pilot project to install radar (dynamic) feedback speed signs. A survey of neighbors regarding this proposal yielded a 50% response rate (14 out of 28). Of those households that responded, 71% (10 of 14) indicated their approval of the proposal to install radar feedback signs. Background / Analysis: In the fall of 2015, residents of Seventh Avenue, between Court Street and Glendale Road, submitted a petition to the City seeking consideration for the traffic calming process. A traffic study determined that the street qualified for the program based on speed and volume. The speed limit on Seventh Avenue is 25 MPH. Southbound speeds vary with 15% of drivers traveling in excess of 34 MPH, while 15 % of northbound vehicles are traveling at 29-32 MPH. These measurements meet the minimum threshold for the traffic calming program, which requires that 15% of drivers are exceeding the speed limit by 5 MPH or more. Seventh Avenue provides an important north-south connection for the larger eastside neighborhoods—the only north-south through street between First Avenue and Muscatine Avenue/Evans Street. Average daily traffic volumes measured during the study period indicated more than 2,700 vehicles per day. Pavement widths can influence vehicle speeds, with narrower widths typically discouraging speeding. The pavement width on this portion of Seventh Avenue is 25 feet, which is narrower than the current minimum standard of 26 feet. On-street parking can also serve to slow vehicle speeds. On-street parking is permitted between Morningside Drive and Glendale Road but is prohibited along other portions of the street in order to accommodate peak hour traffic, including school buses. Block lengths/frequency of intersections can also influence speed. Intersections along this portion of the street occur every 210 to 400 feet, well within the 300- to 600-foot standard in the subdivision regulations. Staff reviewed the traffic study and street context with the City Engineer, Streets Department, and the Fire Department to consider appropriate ways to address the speeding issue. An all- way stop was considered at the intersection of College and Seventh, but was not warranted based on traffic counts on College Street and due to the confusion created by the adjacent intersection with Wilson Street. Staff concluded that radar feedback signs may provide an effective means for lowering speeds in this situation. A review of the literature indicates that radar feedback signs are effective in reducing the number of vehicles traveling ten or more miles over the speed limit. Studies also indicate that radar feedback signs are most effective in conjunction with school zones. While Seventh Avenue is not a school speed zone, it is a primary route for those commuting to City High and the peak travel period is concurrent with school hours. Staff recommends installation of radar feedback signs along this portion of Seventh Avenue as a pilot study and recommends against additional installations of radar feedback signs until after the end of the study period. Staff will re-evaluate speeds 6 and 12 months after installation to measure their effect on speeds. Staff recommends that signs be removed if they do not produce a substantial sustained reduction in speeds or if maintenance and reliability becomes an issue. Neighborhood Process: Funding for traffic calming projects is allocated from a line item in the CIP (S3816). The cost of a single feedback sign is $2,500. Staff is recommending 2 feedback signs–one for northbound and one for southbound traffic.