November 11, 2003
SUBJECT: All-Way Stop Signs at the Intersections of Floyd Avenue at Carlisle Way and Lochinvar Avenue at Swallow Drive.
REPORT IN BRIEF
In response to citizen requests, staff has analyzed traffic operations at the intersections of Floyd Ave/Carlisle Way and Lochinvar Avenue/Swallow Drive. The analysis took into consideration traffic volumes at the intersection, accident history, safe approach speeds, visibility, schools and any unusual conditions to determine whether or not change in traffic controls are warranted for this intersection. The purpose of these studies was to determine the need to install All-Way Stop signs at these intersections. Floyd/Carlisle passed the All-Way Stop Warrant with a total of 35 points (minimum of 18 pts. needed).
There were two studies conducted by staff for the intersection of Lochinvar/Swallow. This location did not qualify through both studies. However, staff is recommending installation of an All-Way Stop at this location due to extraneous conditions not captured in warrant analysis, as well as, support from the surrounding residents. Lochinvar Avenue at Swallow Drive is a “Y” shaped intersection, with two yield signs on Swallow (minor street) and a stop sign on west bound Lochinvar (major street). This is an uncommon intersection where the major street is stopping for traffic on the minor street. The physical layout of the intersection affects visibility and intuitive driver decision regarding traffic control. The intersection of Lochinvar/Swallow is located in a residential neighborhood. Swallow runs north/south connecting Homestead Road to Lochinvar Avenue. Lochinvar runs east/west connecting Dunford Way to Lawrence Expressway. Peterson Middle and Laurelwood Elementary schools are located close by, which generates high volume of vehicles traveling through this intersection. There is high pedestrian/bicyclist activity in this area; school children riding their bicycles to and from these schools share the right of way with vehicles.
As a result of these studies/road geometry, staff recommends that all-way stop signs should be installed at both locations. According to the Municipal Code, all multi way stop installations must be approved by the Council.
BACKGROUND
Due to periodic request by citizen’s for traffic calming, these intersections have each been the subject of numerous traffic studies during the past years. Both intersections have one or two way stop signs on the major street, which is uncommon in the Traffic Engineering practice. Commonly, the stop sign(s) are placed on the minor street(s) to allow vehicles on the major street to have right of way.
In addition to intersection related studies, staff has conducted traffic calming related volume and speed studies along Swallow Drive. The study results showed that Stage 1 traffic calming actions are warranted. Devices being installed include speed limit pavement legends as well as additional speed limit signs. The recent stop study was a result of the traffic calming investigation, and installation of stop signs is consistent with Stage 1 traffic calming.
EXISTING POLICY
The City’s Land Use and Transportation Element (LUTE) policy C3.4.7 states that staff should “Conduct periodic analyses of roadway facilities and collision data in order to assure safe, efficient traffic flow.”
DISCUSSION
Floyd Avenue and Carlisle Way
The intersection of Floyd/Carlisle is located in a residential neighborhood. Floyd runs north/south connecting Fremont Avenue to Dunholme Way. Carlisle Way runs east/west connecting Bittern Drive to Mallard Way. Currently the intersection is controlled by two-way stop signs with Floyd Avenue stopping for Carlisle Way traffic. Stocklmeir Elementary School is located close by which generates significant traffic and high pedestrian activity. There are no sidewalks on all approaches; pedestrians and bicyclist share the roadway with vehicles. Parking is allowed along all approaches, which might affect visibility of vehicles on the side streets or pedestrians walking along the roadway. Both Floyd Avenue and Carlisle Way have horizontal road curvature that affects visibility when approaching the intersection. Multi-way stop signs were warranted for Floyd/Carlisle based on the state required All-Way Stop Analysis with a total of 35 points (minimum of 18 points needed for a one or two-way stop sign). This warrant has not been satisfied in past studies.
Lochinvar Avenue and Swallow Drive
Lochinvar Avenue at Swallow Drive is a “Y” shaped intersection, with two yield signs on Swallow (minor street) and a stop sign on WB Lochinvar (major street). Again this is an uncommon intersection where the major street is stopping for traffic on the minor street. The unusual geometry and atypical control increases the potential for drivers to make incorrect assumptions about the roadway controls. When combined with the use characteristics of the intersection, staff believes that an all-way stop is the safest form of control for the overall conditions present. The intersection of Lochinvar/Swallow is located in a residential neighborhood. Swallow runs north/south connecting Homestead Road to Lochinvar Avenue. Lochinvar runs east/west connecting Dunford Way to Lawrence Expressway. Peterson Middle School and Laurelwood Elementary School are located close by, which also generates high volume of vehicles traveling through this intersection. There is high pedestrian/bicyclist activity; school children riding their bicycles to and from these schools share the right of way with vehicles.
Due to the road geometry and confusion inflected on drivers upon approaching Lochinvar/Swallow, staff conducted two documented Stop Warrant Studies for this intersection, one dated Feb. 19, 1998 and the most recent dated, Nov. 9, 2001. In the recent study, the intersection had a total score of 13 pts. (20 pts. are needed for All-Way Stop sign). Even though it did not qualify through the study, based on good engineering judgement/safety and the road geometry, staff recommends that two more stop signs be placed at this intersection. One stop sign would go on northbound Swallow Drive and one on eastbound Lochinvar Avenue.
Municipal Code Section 10.08.190 states that the City Council shall designate intersections where three or more approaches shall be required to stop.
FISCAL IMPACT
The Department of Public Works operating budget would cover the cost of installing a total of four new stop signs and pavement markings. Two stop signs on east and westbound Carlisle Way, one stop sign on eastbound Lochinvar Avenue and one stop sign at northbound Swallow Drive. Grinding out the yield legends and installation of new stop legends would also be required. Funds are available in the existing operating budget.
PUBLIC CONTACT
Notification of this hearing was mailed to residents within 300 ft of the intersection (all approaches) and neighborhood groups. This item was posted with the Council Agenda. Reports to Council are also available at the City Library and the City's Web Site
ALTERNATIVES
1. Approve the attached resolution (Attachment E) to convert the intersections of Floyd Avenue/Carlisle Way and Lochinvar Avenue/Swallow Drive from a one/two-way stop to an all-way stop.
2. Do not convert the intersections of Floyd Avenue/Carlisle Way and Lochinvar Avenue/Swallow Drive to All-Way stop controlled intersection.
RECOMMENDATION
Staff recommends Alternative No. 1.
Prepared by:
Wahid A. Amiri
Traffic Engineering Assistant I
Reviewed by:
Jack Witthaus
Manager, Division of Transportation/Traffic
Reviewed by:
Marvin A. Rose
Director, Public Works
Approved by:
Robert S. LaSala
City Manager
Attachments
A. Aerial photo shot of the existing lane configuration/road geometry at Lochinvar Avenue and Swallow Drive.
B. Aerial photo shot of the existing lane configuration/road geometry at Floyd Avenue and Carlisle Way.
C. Copy of All-Way Stop Sign Warrant studies for Lochinvar/Swallow. (.pdf format)
D. Copy of All-Way Stop Sign Warrant studies for Floyd/Carlisle.
E. Resolution