Linley Valley West
Detailed design for the phased multi-lane roundabout is 100% complete and the project is currently out for Tender. This project is identified in the 2017-2021 Capital Plan for construction in 2017. Construction is expected to begin in late April lasting through to the end of 2017. Pre-construction work is currently underway including tree clearing and contacting affected businesses and residents. More information and updates during the construction phase of the work can be found at the City of Nanaimo Current Construction Projects webpage.
Where we came from…
Linley Valley West is a new neighbourhood currently under development within the western portion of Linley Valley. Primary access was historically to be provided by Linley Valley Drive, however, the expansion of Linley Valley Park in 2014 reduced future population projections resulting in the re-evaluation of access requirements at neighbourhood build-out.
In October 2015, two access options were presented to the public and input gathered through a consultation process:
Option 1: A new road would be constructed linking Linley Valley Drive to Rutherford Road across from Nelson Road. At the intersection a new traffic signal or roundabout would be developed; or
Option 2: Existing neighbourhood streets would be utilized to link to Rutherford Road at Vanderneuk Road and Brookwood Drive; with a new traffic signal developed at the intersection of Rutherford and Vanderneuk roads.
Consultation results included strong support for Option 1 – A new road linking Linley Valley Drive to Rutherford Road at Nelson Road (80% support) and at the intersection of Rutherford / Nelson there was a preference for a roundabout (72% support) over a traffic signal. Feedback also highlighted concerns about speeds and grades along and difficulty for pedestrians / cyclists to cross the Rutherford Road Corridor; concerns were also raised about the potential for short cutting along Nelson Road.
Based on consultation feedback, technical and financial analysis, Option 1 plus improvements to the McGregor Creek multiuse path crossing of Rutherford Road and the potential for future traffic calming on Nelson Road was recommended to Council in December 2015.
The Improvement Concept (Fall 2015)(PDF) will form the starting point for functional design.
At the December 7th, 2015 City Council Meeting, Council supported Option 1 and directed staff to:
- Prepare detailed design drawings for the roundabout and associated roadworks at the intersection of Rutherford and Nelson Roads.
- Bring forward updated costing and timing option for consideration in advance of the 2017-2021 Capital Plan.
Where we are…
Following Councils direction, a transportation design consultant was retained to complete a detailed traffic analysis of the proposed Nelson / Rutherford / New Road intersection and a functional design for the intersection, connector road and multiuse pathway connections.
Future traffic projections that included full build-out of the Linley Valley West neighbourhood and accommodation for background growth on the Rutherford Road corridor were generated for 2031.
Single Lane Roundabout Analysis
As a starting point a single lane roundabout was tested against future projected traffic volumes. A single-lane roundabout was the recommended intersection configuration in December 2015 based on typical safety performance, speed mitigation, traffic capacity and life cycle costs. Early high-level traffic analysis indicated that future volumes would be within the typical capacity of a single lane roundabout. Subsequently a more detailed analysis identified that due to the large proportion of traffic on Rutherford relative to side streets (Nelson / Linley Valley West Access) the approaches on Rutherford would exceed their capacity in the morning (southbound) and afternoon (northbound) peak periods. During these periods, single-lane approaches on Rutherford Road would experience queuing and wait times on opening day with queuing/delay becoming excessive by 2031.
Multilane Roundabout Analysis
Subsequently, to address capacity constraints of a single lane roundabout, a multi-lane roundabout option was developed and evaluated. The multilane concept would provide a good level of service at neighbourhood build-out with dual-lane entries / exits on Rutherford Road and single lane entries / exits on Nelson Road and the new access road to Linley Valley West.
The proposed second lane on Rutherford would only extend a short distance beyond the roundabout; a drawing of the multi-lane roundabout concept for the intersection of Rutherford / Nelson / Linley Valley West Access is provided below.
An example of a similar multilane roundabout design is presented below from Ira Needles Road in Kitchener, Ontario.
For an interactive view of the above multilane roundabout, you can access Google street view to see what the approach would be like from Rutherford Road (Google Street View) and leaving Linley Valley West (Google Street View).
While a multilane roundabout provides good future capacity it also introduces a number of challenges relative to a simpler single-lane roundabout configuration, including;
- Geometric Layout – The footprint of the roundabout and approaches on Rutherford Road get larger. Due to a constrained layout, larger vehicles such as trucks and buses will occupy both lanes as they traverse the roundabout. The offset layout (to minimize impacts on the west side of Rutherford) may allow some southbound vehicles to travel through the roundabout at higher speeds.
- Property Impacts – The larger footprint has greater impacts on adjacent private parcels.
- Construction Costs - Property and footprint changes increase construction costs.
- Complexity – While multi-lane roundabouts are common in many jurisdictions, and eventually will come to Nanaimo, this would be the region’s fist example and would require a greater level of user education.
- Safety – While multi-lane roundabouts typically have less collisions and less severe collisions than signalled intersections, the reduction is not as large as seen in single-lane roundabouts. Where drivers are unfamiliar with multi-lane roundabouts they can see higher initial collision rates; though with use comes familiarity and these rates tend to decrease over time.
Signalized Intersection Analysis
Considering these challenges the design team revisited the signalized intersection concept. Several intersection configurations were reviewed, with the preferred arrangement, typical single lane approaches with left turn bays on all approaches and a dedicated westbound right turn into Linley Valley West is shown in Figure 2. Detailed traffic analysis projects this intersection would have a good level of service at neighbourhood build-out; similar to the multi-lane roundabout option. However, in contrast to the multi-lane roundabout this option is much less complex and has lower construction costs.
Comparison of Intersection Options
Information from the detailed traffic analysis, preliminary design and estimate has been consolidated below.
|Multi-Lane Roundabout||Signalized Intersection|
|Traffic Capacity||Both options have sufficient capacity at neighbourhood build-out|
|Speed Mitigation||Significant but not as effective as single-lane configuration. Southbound vehicles may have higher speeds due to offset geometry.||Some impact when signal services Nelson / Linley Valley West Access. Other street design elements, ie bike lanes, on-street parking, street trees can mitigate speeds.|
|Traffic Safety||Reduction in number and severity of collisions but less so than single-lane configuration.||Expect typical uncongested signalized intersection performance.|
|Capital Costs||$750,000 more in capital costs for the roundabout option.|
|Private Property Impacts||Impacts three private parcels.||No identified land impacts.|
|Accommodating Large Vehicles||Buses and larger trucks will occupy both lanes within the roundabout.||No issues.|
In general, both intersection options (multi-lane roundabout / traffic signal) provide sufficient future traffic capacity. The multi-lane roundabout maintains the benefits of roundabouts such as reduced speeds and collision rates/severity but to a lower degree than the simpler single-lane roundabout configuration; it does however incur significant additional costs and complexity for design, construction and users. The signalized intersection is very familiar to drivers and could be constructed at a significantly lower cost. In both scenarios the new Linley Valley West access road would be constructed eastward from the intersection to link with Linley Valley Drive.
With either intersection option other components of this project are proposed to address issues raised during the public consultation last fall, including:
- Consultation results highlighted the challenges of crossing Rutherford Road from the new development areas in Linley Valley West to established neighbourhoods (and schools) along Nelson Road. Proposed improvements would create two new pedestrians/cyclist crossings of Rutherford Road at McGregor Creek (multiuse trail crossing) and the new Rutherford / Nelson / Linley Valley West Access intersection. A multi-use trail connection from the new intersection to the end of Linyard Road will provide a well-graded route to Linley Valley Drive for pedestrians and cyclists.
More information on multiuse trail links
- Residents along Nelson Road highlighted concerns that a new intersection could lead to higher speeds / volumes on their street. It is proposed that traffic volumes and speeds before and after intersection construction be monitored and if conditions change; traffic calming be considered with support from Nelson Road residents.
More information on Nelson and Rutherford traffic calming
Where we are going…
Both the multi-lane roundabout and signalized intersections options have advantages and disadvantages. The multi-lane roundabout is safer for motorists due to lower vehicle speeds and fewer conflict points, however there are existing site constraints that result in considerably higher construction costs and impacts on adjacent properties. To minimize impacts the design used a small diameter layout which will create some challenges for buses and larger commercial vehicles and the offset layout may allow some vehicles to travel through the roundabout at higher speeds which could erode safety benefits.
The signalized intersection would largely utilize the existing pavement and curb lines resulting in lower construction costs and no land acquisition. Going forward, signal timings can be altered to optimize the intersection as future traffic from Linley Valley West increases.
Street design features in both options, that physically and/or visually narrow the roadway would be introduced along Rutherford to mitigate speeds and pedestrian/cycling connections would be enhanced helping residents access portions of their neighbourhood beyond Rutherford Road.
Previous Activities and Documents
In January 2016, 5290 Rutherford Road was purchased by the City to facilitate a new link road from Rutherford Road to Linley Valley Drive.
At the December 7th, 2015 City Council Meeting, Council directed staff to:
- Exercise the option to purchase agreement for 5290 Rutherford Road
- Prepare detailed design drawings for the roundabout and associated roadworks at the intersection of Rutherford and Nelson Roads
- Bring forward updated costing and timing option for consideration in advance of the 2017-2021 Capital Plan.
For copies of the Meeting Agenda, Council Report, Public Consultation Summary and Display Boards from the open house, please see the links below:
- To view the December 7th Council Meeting Agenda and Staff Report (see Item 8(d) page 108)), please click here [PDF - 117MB]
- To view the Council Report (extracted from the agenda to reduce file size), please click here [PDF - 2.9 MB]
- To view the Public Consultation Summary (extracted from the agenda to reduce file size), please click here [PDF - 4.6 MB]
- To view the Display Boards from the October 8th Open House, please click here [PDF - 4.4 MB]