Laserfiche WebLink
City of Tukwila My WebLink |HelpSearch Tips |About |Sign Out
City of Tukwila <br />Public Works Department - Bob Giberson, Director <br />TO: Transportation and Infrastructure Committee <br />FROM: Robin Tischmak, Acting Public Works Director <br />CC: Mayor Ekberg <br />DATE: October 6, 2017 <br />SUBJECT: Speed Cushion Pilot Project - Implementation Criteria <br />Project No. 91610410 <br />Allan Ekberg, Mayor <br />ISSUE <br />Develop implementation criteria for traffic calming features that include speed cushions and/or radar <br />speed display signs on residential streets in the event that funding is programmed in future budget <br />cycles. <br />BACKGROUND <br />The City's Capital Improvement Program (CIP) has historically included a Neighborhood Traffic <br />Calming Program that is unfunded due to staffing needs. A speed cushion pilot project was <br />implemented on S 160th St to determine the effectiveness of innovative speed cushions in conjunction <br />with radar speed display signs. Formal criteria are desired for the possible implementation of similar <br />improvements on other residential streets throughout the City in case funding is budgeted to expand <br />this effort into an ongoing program. <br />DISCUSSION <br />The three most common engineering criteria used to justify traffic calming initiatives are related to <br />speeding, traffic accidents and vehicle volumes. High speeds and a history of traffic accidents are <br />primary safety concerns. Vehicle volumes are an indicator of the type of roadway facility and would be <br />used to determine the cost effectiveness of installing improvements. Very low volume streets may not <br />merit the cost of traffic calming measures while higher volume streets (those arterials intended to move <br />traffic) may likely have the adverse consequence of causing cut -through traffic on adjacent streets. In <br />addition to the common criteria mentioned above, other factors can be evaluated for consideration such <br />as: population density, school routes, existing pedestrian facilities, transit routes, or other <br />characteristics specific to a street under consideration. <br />After evaluation, a determination to install radar speed display signs, speed cushions, or other traffic <br />calming measures will be made. Evaluations could include a determination of no action, installation of a <br />singular item, multiple items, or a progressive approach from radar speed display signs to speed <br />cushions. <br />FINANCIAL IMPACT <br />There is currently no financial impact as there are no funds budgeted for this program. <br />RECOMMENDATION <br />For information only. <br />W:\PW Eng1PROJECTSIA- RW & RS Projects\Traffic Calming1160th Speed Cushion Pilot Project\info memo TIC speed cushions.docx <br />6300 Building • 6300 Southcenter Boulevard Suite ioo • Tukwila, WA 98188 • 206-433-0279 <br />Tukwila City Hall • 6200 Southcenter Boulevard • Tukwila, WA 98188 • 206-433-1800 • Website: TukwilaWA.gov <br />37 <br />