At the regular Council meeting of Monday, April 12, Council made two short-term decisions on Lanfear hill that will help remedy the current challenges while not drastically impacting traffic patterns or affecting the long-term plans for the road’s reconstruction.
Background:
In March 2021, the City closed the gravel shoulder on Lanfear Drive to pedestrian use due to slope instability and deformation of portions of the gravel shoulder and commissioned a geotechnical consultant to conduct a safety assessment of the roadway and hill slopes. The geotechnical report from Golder Associates Ltd. recommended the gravel shoulder remain closed until a suitable walking surface is restored. It also recommended that the City repair all vertically displaced sections of the gravel shoulder this summer in dry conditions. Staff presented their recommendations based on this report to Council at the April 12 meeting.
Repairs to be completed:
The first short-term decision the City of Terrace made was to complete minor repairs only on the gravel shoulder in order to return the shoulder to the existing width, minimize costs, reduce construction time, and help ensure pedestrians and cyclists can return to using this route as soon as possible.
This repair option involves removing existing material from the gravel shoulder and replacing it with compacted rockfill and base gravels during dry weather periods. This has an estimated minimum lifespan of five years. If poor soil conditions are found, then further remediation will be required, and it is expected that wire-faced mechanically stabilized earth (MSE) walls will be installed in these areas. As a preliminary estimate, it has been assumed that approximately 30% of the shoulder repairs will require MSE walls and will have a minimum lifespan of over 20 years.
With the assumptions of 70% rockfill and 30% MSE wall, the estimate for construction duration is up to eight weeks with a total cost of up to $360,000. The $360,000 cost of these repairs will be allocated from the Northern Capital and Planning Grant Reserve, and the 2021 financial plan will be amended accordingly.
An alternative repair option was provided to repair all failed sections of the shoulder with MSE walls and forgo and short-term rockfill repairs. This repair would provide a longer lifespan and had an estimated cost of $900,000. “While this alternative option would provide a longer lifespan and a wider shoulder in the areas that are eroding, it would not align with the design identified in the Transportation Master Plan to fully upgrade Lanfear hill to a higher standard. No matter which option we choose now, it’s likely we will have to rip that out when it comes time to complete full upgrades on the hill,” said David Block, Director of Development Services and Interim Director of Engineering and Public Works and Engineering.
Temporary traffic pattern modifications:
The second short-term decision was not to implement any lane closures or change vehicle traffic patterns on Lanfear Drive. Council heard from staff about possible temporary traffic pattern modifications, with three options provided that would allow for one lane of traffic and the other for pedestrian and cyclist use. Signalized alternating traffic was not recommended since there is insufficient space for vehicles to queue at the top and bottom of the hill. AM/PM alternating traffic was also not recommended since the robust electronic signage would be more expensive and require a longer learning curve for users.
One-direction traffic was recommended as the best choice of the three, since it would be easiest to implement for the lowest cost. However, staff outlined the additional challenge of choosing which travel direction is preferable and the challenges of adding barriers to separate the vehicles from pedestrians. Pedestrian and vehicle safety, the needs of emergency services, traffic volumes, costs, traffic rerouting, winter maintenance, and school and transit buses were all examined as part of the process. A vehicle lane closure would extend emergency response times to some residential areas by an estimated 2–3 minutes. Increased delays could potentially be life-threatening in an ambulance response call or result in a significant increase in damage to property in the event of a fire.
Ultimately, staff did not recommend any traffic pattern modifications, and Council agreed with this recommendation.
Staircase options:
Council also asked staff for an update on staircase options from the Horseshoe to the Bench. Council have noted that during any closure of the hill, including the full reconstruction when it occurs, will require rerouting pedestrians for an extended period, and using the various existing pathways up the hillside may not be feasible for all pedestrians. Staff indicated that a grant application was submitted last year for a staircase at Eby Street and anticipate hearing back about that grant in mid-2021. “We have a design for a staircase at that location, which is why we applied for the grant for Eby, but if we were to get this grant, we think we could go back to the grant provider to request to move the staircase to the Thomas Street location instead, making it an option for those who would normally travel up and down Lanfear,” said Block.
Lanfear hill study:
The full Lanfear Hill Improvement Project is still ongoing; the City continues with preliminary design work to strengthen future grant applications for this $10-million project. The 2021–2025 five-year plan includes $150,000 from the Northern Capital and Planning Grant reserve for a preliminary design, including a detailed geotechnical investigation, and staff have indicated that a request for proposals will be developed soon to get started with that project.
The full report to council can be found here: https://terrace.civicweb.net/document/10403
For background information as well as future updates on Lanfear Hill, please see our new page, https://www.terrace.ca/lanfear-hill