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HomeMy WebLinkAboutA003 - Council Action Form dated December 19, 2006 old CAS a� ITEM # DATE 12-19-06 COUNCIL ACTION FORM SUBJECT: SPEED LIMIT ON SOUTH DAKOTA AVENUE BACKGROUND: At the December 12, 2006, City Council meeting, staff gave a presentation concerning the traffic operations on South Dakota Avenue from U.S. Highway 30 to Lincoln Way. The study was initiated from a citizen's concern regarding difficulty in exiting Mary Greeley Medical Center's Israel Family Hospice House located at 400 South Dakota Avenue. The study revealed that traffic was operating below the 40 mile per hour (mph) speed limit in this section (85th percentile of 38 mph) and that adequate sight distance and gaps in traffic were available throughout the corridor. The study also provided data showing that traffic was operating at an 85th percentile speed of 35 to 40 mph in the section between Clemens Boulevard and Lincoln Way, which is currently regulated at 25 mph. Staff found this 25 mph section was implemented many years ago in support of school pedestrian route plans, which are now outdated. The recommendation from staff was to keep the 40 mph section as it exists and to change the speed limit in the 25 mph section to 35 mph. A number of issues were discussed during the presentation that required further consideration as follows: • The posted speed limit of 40 mph is too high due to high number of pedestrians and bicyclists using the multi-use path adjacent to the street. • The speed limit should be established so that it is consistent throughout the South Dakota Avenue corridor. • There is a long distance between the existing signalized crossings at Lincoln Way and Mortensen Road. Crossing South Dakota Avenue within this section may be difficult. In order to address the concerns of pedestrian proximity and consistency of speed limits, staff feels that it would be appropriate to establish a 35 mph speed limit for the entire length of South Dakota Avenue. In response to direction from City Council, staff conducted an additional analysis relating specifically to pedestrians using the shared-use path crossing located approximately 425 feet north of Clemens Boulevard/Hospice Driveway. Currently, this is the designated crossing for the College Creek Recreational Trail, which will eventually be extended through Nature's Crossing Subdivision. Staff measured a crossing distance (curb-ramp to curb-ramp) of 42 feet for this existing shared-use path crossing north of Clemens Boulevard. Using the standard design walking speed of four feet per second, staff determined the time it would take most pedestrians to cross South Dakota Avenue. This was then used to evaluate the size of gap required between vehicles in order to make a safe pedestrian crossing Using this criterion and the previously collected traffic data, it was found that the average wait a pedestrian would experience in order to find an acceptable gap during PM peak hour traffic would be 18 seconds. However, the average time a pedestrian may wait during the day is four seconds. This wait time for pedestrians is well within the acceptable delay expected for an arterial roadway. Staff was also directed to explore creative solutions to address concerns related to pedestrians attempting to cross midway along South Dakota Avenue. With the proposed future improvements to widen South Dakota Avenue to a planned five-lane cross section, staff feels that a refuge island could be considered as a designed pedestrian amenity as part of this project. This refuge island, which would encompass the full center turn lane width (12 to 14 foot), may provide pedestrians with the option to make two shorter crossing movements rather than one large movement across the entire width of the roadway. In doing so, it was found that this also affords pedestrians the option to utilize smaller gaps in the traffic stream. This would result in reducing the average pedestrian wait time in half. ALTERNATIVES: 1. Direct the City Attorney to modify the ordinance to change the speed limits along South Dakota Avenue by establishing a 35 mph zone from the centerline of Lincoln Way to the overpass with U.S. Highway 30. This action will also initiate an ordinance change to remove the reference to a special 20 mph zone at Todd Drive (new recommendation). 2. Direct the City Attorney to modify the ordinance to change the speed limits along South Dakota Avenue by establishing a 35 mph zone for the first 1500 feet south of the Lincoln Way centerline, and a 40 mph zone from that point south to the overpass with U.S. Highway 30. This action will also initiate an ordinance change to remove the reference to a special 20 mph zone at Todd Drive (previous recommendation from 12-12-06). 3. Direct staff to lower the speed limits along South Dakota Avenue. However, this likely would not result in greater available gaps or slower operating speeds. Setting speed limits lower than the speed at which drivers feel they may safely operate would likely lead to vehicles bunching together, which may reduce available gaps. 4. Direct staff to explore other alternatives. 5. Do not change the speed limits on South Dakota Avenue. MANAGER'S RECOMMENDED ACTION: Establishing a speed limit of 35 mph for the entire South Dakota Avenue corridor would address the concerns that were raised and would be consistent with the operational characteristics of the roadway. It was also found that average wait times for a pedestrian to cross South Dakota Avenue at the existing College Creek trail crossing are well within expected limits. In order to address possible future concerns due to roadway widening, installation of a pedestrian refuge island will be considered. Therefore, it is the recommendation of the City Manager that the City Council adopt Alternative No. 1, thereby directing the City Attorney to modify the ordinance to change the speed limits along South Dakota Avenue by establishing a 35 mph zone from the centerline of Lincoln Way to the overpass with U.S. Highway 30. This action will also initiate an ordinance change to remove the reference to a special 20 mph zone at Todd Drive.