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Climate-resilient public transit: why and how? CPCS explains.

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A primer on public transit resilience in a changing climate based on our on-demand InfraSight webinar with CPCS transportation advisors.

In this article:

What is climate resilience?

Climate resilience is the ability to withstand and recover from these shocks and stresses. 

  • Climate stressors are the events or factors from the natural environment that impact ecosystems (e.g., precipitation, heat, cold, wind). In turn, these climate stressors create climate risks.

  • Climate risk is the risk of harm from anticipated climate stressors. For example, flooding from extreme precipitation or the heightened risk of wildfires sparking due to serve storms with lightning strikes. 

The challenge of resilience

Increasing the resilience of public transit systems is challenging, since climate stressors can vary by frequency, severity and geography. Each transit system and its assets must be analyzed separately with tailored adaptation efforts. Climate adaptation refers to taking actions to make systems and infrastructure more resilient to climate change.

One of the greatest challenges is finding a balance between the level of resilience and the scale or cost of an adaptation effort. It is challenging to predict the frequency and severity of future climate events. Therefore, it can be difficult to communicate the value of avoiding a future disruption, which may be less severe or non-existent since the adaptation mitigated or eliminated the risk. Since the benefits of adaptation measures are not guaranteed, it can also be difficult to communicate the value of these efforts to decision-makers and stakeholders.

What does climate change mean for public transit systems?

Climate stressors affect all parts of the transit system.

Intense precipitation

  • Flooding of roads, bridges, rail lines.

  • Snow and ice accumulation can lead to loss of traction on roadways or track guidelines.

  • Water getting into tunnels and other subterranean structures can damage infrastructure.

Extreme heat

  • Poor air quality caused by wildfire smoke can lead to failure of HVAC systems and cause operational health and safety risks to workers.

  • Overheating and failure of electrical systems.

  • Heat can cause train tracks to expand and warp, leading to a risk of train derailment.

Intense cold

  • Low temperatures can cause structural cracks in track infrastructure.

  • Reduced operating range of battery electric vehicles.

Seasonal temperature variations

  • Melting permafrost causes unstable of geotechnical conditions, causing segments of road and track that were once built on a stable surface to become unstable.

  • Freeze/thaw cycles can cause damage to roads, including pothole formation.

High winds and severe storms

  • Winds can knock down trees or telegraph poles, causing power outages.

  • Impaired visibility due to winds and intense precipitation can be unsafe for transit operation.

  • Wind damage to infrastructure and risk of debris obstructing roads and track guideways.

Storm surge and sea-level rise

  • Coastal erosion can deteriorate road and rail conditions.

  • Corrosion of metallic infrastructure due to sea water.

Decarbonization/electrification

Decarbonization presents positives for climate change mitigation. However, it can also create some challenges in terms of additional considerations for resilience. For instance:

  • Risks to the electrical grid, such as blackouts, are more likely to impact the transit service’s operation for electric vehicles.

  • Electric vehicles are heavier due to the batteries needed to operate them, which could accelerate road wear.

Project delivery methods

There has been a push towards increased involvement from the private sector and use of public-private partnerships to deliver infrastructure projects.

This involves risk sharing with the private sector, which leads to a greater need for understanding of climate change risks and allocation of those risks between the public and private sector over the long term.

Climate emergencies increasing demands on public transit

Public transit systems must be reliable and accessible in times of climate emergency as the use of public transit assets are often integrated in emergency response measures. For example, using transit buses to evacuate communities threatened by wildfires, or transporting vulnerable population groups to cooling centres during heatwaves.

How can we improve the resilience of public transit systems?

Climate change risk is a product of vulnerability and criticality, which must be evaluated for the different assets and components of a transit system.

  • Vulnerability includes how close or exposed the asset is to the hazard, how sensitive the asset is, and its ability to adapt in response to the risk.

  • Criticality is how important the asset is to the delivery of transit services.

What do we need to do differently to adapt?

Hardening or protecting infrastructure: using different materials and design methods to build out stronger infrastructure and implementing systems to detect hazards before they become more problematic.

Relocation of infrastructure or services: rerouting, isolating, or relocating sections of the transit system that are more exposed or vulnerable to hazards to prevent damage.

Operational and maintenance (O&M) adjustments: developing new or contingent systems or technologies to better address the challenges caused by climate-related hazards.

The road ahead to resilience

In planning resilient infrastructure, it’s important to acknowledge that it comes at a cost. However, spending more now to build resilient systems may save time and money in the future by reducing the impact of operational disruptions and the need of rebuilding infrastructure following a severe climate event. Climate resilience can be factored into design evaluation, tendering award criteria, and infrastructure access agreements.

Go deeper: learn more about CPCS’s climate change advisory for sustainable infrastructure.

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