The City of EdmontonAttachment 2
Executive Summary
1Introduction
Stony Plain Road (Highway 16A) west of Anthony Henday Drive is currently classified as a future rural divided freeway by Alberta Infrastructure and Transportation. Stony Plain Road between Anthony Henday Drive and 231 Street (Hillview Road) is within the City of Edmonton’s jurisdiction, but existing agreements between the City and the Province of Alberta outline future treatment of the roadway.
The existing Stony Plain Road has a rural divided cross-section carrying eight lanes near Anthony Henday Drive and four lanes near 231 Street, and is serviced by an intersection at 231 Street (Hillview Road) and an interchange at 215 Street (Winterburn Road). An assortment of collector-distributor roads, service roads, and frontage roads provide access from the corridor to adjacent business and residential lands. There is currently no direct access from the Stony Plain Road mainline to businesses or residences.
The City of Edmonton’s Transportation Department retained Associated Engineering to develop long-term concept plans for Stony Plain Road. The Stony Plain Road Concept Plan was commissioned to provide guidance to respond to development applications along the study area (such as area structure plan amendments, neighbourhood structure plans, and proposed subdivisions), and to protect lands required for future roadway improvements.
The Stony Plain Road Concept Plan was a collaborative effort by Associated Engineering and Gray Scott Consulting Group. Associated Engineering was the lead consultant and performed planning, engineering, and design; Gray Scott Consulting Group provided public consultation guidance throughout the study.
A project steering committee provided guidance to the consulting team. The project steering committee included representatives from the City of Edmonton’s Transportation department (Development and Capital Planning, Strategic Transportation Planning, and Streets Engineering), and Alberta Infrastructure and Transportation’s Planning and Design, Technical Standards Branch.
Additional input was obtained from other City of Edmonton representatives, from the Transportation Development and Capital Planning, and the Planning and Policy Services departments. Representatives from ParklandCounty were also provided with project updates and the study progressed.
Available Plans
A number of approved and proposed development plans exist near the study area. These include the Winterburn Area Structure Plan, the Lewis Farms Area Structure Plan, a number of proposed amendments to the Lewis Farms Area Structure Plan, and local neighbourhood structure plans.
The Winterburn Area Structure Plan was developed by ParklandCounty in 1980, and was adopted by the City of Edmonton when the Winterburn area was annexed in 1982. The Winterburn ASP defines an area of industrial land to the north of Stony Plain Road, but is out of date and expected to be updated after 2007.
The Lewis Farms Area Structure Plan was first adopted in 1988, and has had periodic updates to change land use and other information. The Lewis Farms ASP defines a mix of residential, commercial, and industrial lands to the south of Stony Plain Road. The original Lewis Farms ASP proposed several connections from Stony Plain Road to the Lewis Farms Area. The most recent ASP amendment proposals eliminate some of the accesses from Lewis Farms to Stony Plain Road and provide access to Stony Plain Road at 231 Street (Hillview Road) and 215 Street (Winterburn Road) only.
The Acheson Industrial Park Area Structure Plan was adopted by ParklandCounty in 1997 to provide development direction for the lands immediately west of the City of Edmonton along Stony Plain Road. The Acheson Industrial ASP provides provisions for Stony Plain Road to function as either an expressway or a freeway; no direct accesses will be allowed from the highway to local businesses. A future interchange is identified on Stony Plain Road at 231 Street; the next access is via the existing Highway 60 interchange.
The Review/Update of the 1984 Functional Plan: Anthony Henday Drive/Stony Plain Road Interchange was developed in 1997 to update the original functional plan for that interchange. The original interchange provided a systems interchange (free-flow in all directions), and provided for a freeway standard for both Anthony Henday Drive and Stony Plain Road. The 1997 update proposed adopting a lesser standard (expressway) for Stony Plain Road, and redesigned the interchange to provide free-flow conditions on both Anthony Henday Drive and Stony Plain Road through traffic, but provided signalized intersections on some of the turning movements.
The City of Edmonton and the Province of Alberta agreed on a bylaw that became known as the Highway Penetrator Agreement. This agreement clearly defined the functionality requirements for all provincial highways between the City of Edmonton corporate limits and the (then) proposed outer ring road (now Anthony Henday Drive). Stony Plain Road (west of Anthony Henday Drive) was defined in this agreement to be built to a freeway standard in its ultimate stage.
The City of Edmonton developed the West End Corridor Urban Design Guidelines in 2005 which provide a vision for future development along Stony Plain Road between Anthony Henday Drive and Hillview Road. These guidelines deal mostly with the landscaping and visual identity rather than with the roadways themselves. The guidelines provide a vision for land use, landscaping, lighting, and signing along Stony Plain Road which would result in a vibrant and sustainable gateway into Edmonton.
Additional background traffic information included functional plans for Winterburn Road south of the Stony Plain Road study area, the Highway 628 Functional Planning Report (between 215 Street and RR 264), intersection traffic movement counts (AADT, AM Peak, and PM Peak), and traffic collision information from the previous five years. An excerpt from Edmonton’s Regional Travel Model was also collected that provided expected long-term roadway volumes and peak hour turning movements at the intersections and interchanges along Stony Plain Road.
The Bridge Inspection and Maintenance (BIM) report for the existing Winterburn Road bridge over Stony Plain Road was also collected. This document provides inspection, maintenance, and other information on the bridge’s condition. Detailed as-built drawings of the bridge were also obtained and reviewed.
Project Issues
Through the project’s first phase, a comprehensive list of issues were developed by the project team with input from the project steering committee and the stakeholder profiling interviews. These issues included:
• Direct access to Stony Plain Road exists to two undeveloped lots within the city limits, and to two landfills in ParklandCounty, just west of 231 Street
• Vertical crest curve just east of 231 Street provides substandard sight lines
• Direct access to Winterburn Road interchange ramp/frontage road
• Both Winterburn Road interchange ramps/frontage roads carry two-way traffic for only a portion of their length
• Four lots southwest of the Winterburn Road interchange have direct access to the ramp/frontage road as well as direct access to 100 Avenue
• 103 Avenue is used by some truck traffic as an alternative to the southbound to westbound loop ramp at Winterburn Road
• The Winterburn Road bridge carries four lanes and will need to be upgraded or replaced
• The eastbound ramp does not connect directly to Winterburn Road
• 199 Street exists as an all-directional access which will ultimately be closed
• Close proximity to the AnthonyHenday interchange may introduce weaving issues on Stony Plain Road
• The current ditch drainage system will need upgrading to accommodate the new roadway
Traffic Analysis
Six preliminary concept plan options were developed that covered a range of traffic capacities. The options had Stony Plain Road operating as an expressway with at-grade intersections to a freeway with partial cloverleaf interchanges. These six preliminary concept plans were presented at the first public open house to receive comments from the public. Based on preliminary capacity analysis, the highest capacity concepts were set aside because the long-term traffic volumes did not necessitate such designs. Three of the original concepts, plus two variations, were carried forward to the detailed modeling stage.
Highway Capacity Manual 2000 methodology was used in conjunction with Synchro/SimTraffic and Highway Capacity Software+ (HCS+) to evaluate each of the five refined concepts. Rating criteria were developed and a criteria weighting system was used to determine the most feasible options. Two of these five concept plans were brought forward and presented to the Project Steering Committee and at the second open house.
These final two options recommended Stony Plain Road operate as a freeway with interchanges at Winterburn Road and Hillview Road. One option provided tight diamond interchanges at both Winterburn Road and Hillview Road. The second option provided Single Point Urban Interchanges (SPUIs) at both Winterburn Road and Hillview Road. The Project Steering Committee reviewed comments from the second open house, and discussed the merits and drawbacks of the two final concepts. Ultimately the tight diamond interchange option was chosen over the SPUI option because of driver familiarity with diamond interchanges, potential lower construction costs, and easier constructability and construction staging.
Recommended Concept Plan
Following detailed traffic modeling and concept alternative evaluation, the recommended concept plan provides simple tight diamond interchanges on Stony Plain Road at both Hillview Road and Winterburn Road. Access to all businesses along the corridor will be through frontage or internal circulatory roadways.
The project team developed geometric design criteria for the Stony Plain Road Concept Plan based on its functionality as an ultimate freeway. The criteria was developed based on guidelines from the City of Edmonton, Alberta Transportation, and the Transportation Association of Canada.
The Stony Plain Road mainline is recommended to carry six core lanes west of Winterburn Road and eight core lanes east of Winterburn Road in its ultimate stage. However, major weave movements and close intersection spacing facilitate a need for an auxiliary lane in each direction between Winterburn Road and Hillview Road. Frontage roads are provided in the concept plan where lands have existing access to a service road or ramp. However, access to these frontage roads are via Winterburn Road and Hillview Road.
The City of Edmonton identifies Winterburn Road as a 24 hour truck route carrying an ultimate six lanes through the Lewis Farms area. Access to Stony Plain Road will be through a tight diamond interchange. Double left turn lanes and channeled right turn bays are provided for all movements. The existing 100 Avenue connection to Winterburn Road is closely spaced to the proposed interchange, but can be accommodated in the long term plans. 100 Avenue will provide access to the commercial businesses south of Stony Plain Road. 103 Avenue will provide access to the frontage road north of Stony Plain Road.
Hillview Road is ultimately planned as a major arterial road bordering the City of Edmonton and ParklandCounty. The recommended Stony Plain Road Concept Plan provides a tight simple diamond interchange that will carry Hillview Road over Stony Plain Road. Predicted high turning volumes at this interchange facilitated the need for double left turn lanes and right turn lanes with channelization for all movements.
The project team has identified that although the existing Hillview Road intersection operates at an acceptable level of service, short term growth in the Lewis Farms area may facilitate upgraded intersection treatment before the ultimate interchange is constructed. Therefore, an interim intersection treatment was recommended. Although traffic signals would increase the Hillview Road approach level of service, such treatment would significantly impact traffic on Stony Plain Road. The project team recommended that with increasing volume on Hillview Road, the City restrict Hillview Road through movements and Hillview Road left turn movements in the interim stage. This would allow for right- and left-turn movements from Stony Plain Road to Hillview Road and right-turn movements from Hillview Road to Stony Plain Road. Such treatment would reduce the number of conflicts while maintaining most intersection movements.
The recommended Stony Plain Road Concept Plan identifies Stony Plain Road as a freeway facility. With such a designation, no direct access to private land will be allowed from either the mainline or interchange ramps. Currently, local businesses have direct access to the Stony Plain Road ramps (both eastbound and westbound). The concept plan identifies that these accesses will be removed and substituted with frontage road access only. Frontage roads would connect to Stony Plain Road via intersections on Winterburn Road at 100 Avenue and 103 Avenue.
The West End Corridor Urban Design Guidelines identify a vision for future development along Stony Plain Road within the study area with respect to landscaping and visual identity. Consistent with the West End Corridor Urban Design Guidelines, the project team for the Stony Plain Road Concept Plan recommend allowing provisions along the Stony Plain Road corridor to implement some of the guideline’s recommendations, including architectural entrance features on the Winterburn Road and/or Hillview Road bridges, and enhanced landscaping and tree planting along the corridor.
Stormwater Drainage
The existing drainage within the corridor is accommodated through ditches and culverts within rural road cross-sections. These ditches were constructed many years ago and are generally flat and poorly drained. The majority of the drainage ultimately discharges into the transportation utility corridor east of the study area en route to a trunk sewer along 102 Avenue.
The project team developed a design philosophy and design criteria. Highlights of the design philosophy include providing ditch or stormwater management facility storage with controlled discharge to the existing trunk sewer along 102 Avenue. The design standards were based on the City of Edmonton’s design standards with a maximum controlled discharge based on the January 2006 Quesnell Storm Basin Study.
Three stormwater design alternatives were developed to provide storage to accommodate the controlled discharge requirements within the study area. The optimum stormwater accommodation within the study area may be some combination of the three alternatives, depending on the final constructed roadways.
Structural Considerations
The existing bridge structure carrying Winterburn Road over Stony Plain Road was constructed in 1972 and requires significant upgrading to accommodate the long term traffic requirements at this interchange. The project team reviewed the City of Edmonton’s Bridge Inspection and Maintenance report and Alberta Infrastructure and Transportation’s Bridge File for the Winterburn Road Structure. The existing bridge carries four lanes across three spans; the ultimate bridge configuration will require ten lanes across just one span. Therefore, the ultimate bridge will be shorter and wider than the existing bridge.
The project team developed a strategy to upgrade the Winterburn Road bridge while utilizing portions of the existing bridge. A traffic accommodation strategy was also developed to illustrate how the bridge upgrades could be accommodated with minimal traffic detours.
Hillview Road currently exists with an at-grade intersection on Stony Plain Road. Ultimately, the interchange requires a ten lane bridge carrying Hillview Road over Stony Plain Road. The project team recommended interim intersection treatment, and has developed a strategy to accommodate traffic detours during interchange construction.
Environmental Considerations
A partial Phase 1 Environmental Impact Assessment was conducted along the study area to determine potential environmental considerations that may need to be further investigated before continuing to construction. The lands near the Hillview Road and Stony Plain Road intersection consist of dry waste landfills, agricultural lands, residential lands, and oil and gas well sites. Near the Winterburn Road interchange the surrounding areas are developed with commercial businesses or residential dwellings. There are no streams, lakes, or wetlands within the study area.
Historical records including aerial photographs, land titles, property use, and local regulatory checks were conducted on select sites within the study area. In general, the commercial businesses operating garage storage, water slides, churches, and motels do not present apparent environmental concerns. The landfills only accept construction and demolition (dry) waste, and also do not have apparent environmental concerns. A number of existing sites in the study area do present potential risk; these include oil and gas well sites, scrap yards, and vehicle sales lots. No environmental infractions have been issued to any of the assessed sites, however further environmental assessments, including groundwater sampling, may be required for some of the sites at the detailed roadway design phase.