Highway Infrastructure in Atlantic Canada

The Critical Role of Highway Infrastructure in Atlantic Canada's Economic Development

Highway infrastructure serves as the backbone of Atlantic Canada's economy, connecting communities, facilitating trade, and supporting the movement of goods and services across Nova Scotia, New Brunswick, Prince Edward Island, and Newfoundland and Labrador. With approximately 42,000 kilometres of highways spanning the four Atlantic provinces, the engineering challenges and opportunities in this sector are both significant and diverse.

The unique geographical and climatic conditions of the Maritime region present distinct challenges for highway engineers. From the freeze-thaw cycles that can reach upwards of 100 annual occurrences in some areas to the coastal salt exposure that accelerates infrastructure deterioration, designing and maintaining highway systems in Atlantic Canada requires specialized expertise and innovative approaches.

Current State of Highway Networks Across the Atlantic Provinces

Atlantic Canada's highway network comprises a complex system of interprovincial corridors, provincial trunk highways, and local connector roads. The Trans-Canada Highway, stretching approximately 1,800 kilometres through the region, represents the primary arterial route connecting Atlantic Canada to the rest of the country and serves as a critical corridor for commercial transportation.

Nova Scotia's Highway System

Nova Scotia maintains approximately 23,000 kilometres of public roads, with the 100-series highways forming the backbone of the provincial network. These controlled-access highways, designed to modern engineering standards, facilitate the movement of over $40 billion worth of goods annually. Key corridors include:

• Highway 102: The Halifax-Truro corridor serving as the province's busiest route with average annual daily traffic (AADT) exceeding 35,000 vehicles in urban sections

• Highway 104: The critical link to New Brunswick and the Trans-Canada Highway system

• Highway 101: Connecting Halifax to the Annapolis Valley and Digby ferry terminal

• Highway 103: The South Shore route linking Halifax to Yarmouth

The Nova Scotia Department of Public Works has identified approximately $2.8 billion in highway infrastructure needs over the next decade, encompassing new construction, rehabilitation, and bridge replacement projects throughout the province.

Regional Connectivity Challenges

The interprovincial connections between Atlantic provinces present unique engineering challenges. The Confederation Bridge, spanning 12.9 kilometres between New Brunswick and Prince Edward Island, represents one of the longest bridges over ice-covered waters in the world. Similarly, the proposed fixed link between Nova Scotia and Newfoundland continues to be studied, with preliminary engineering assessments examining crossing options ranging from 18 to 115 kilometres.

Engineering Design Considerations for Maritime Highways

Designing highway infrastructure in Atlantic Canada requires careful consideration of multiple environmental and geological factors that directly impact construction methodologies, material selection, and long-term performance.

Pavement Design and Climate Adaptation

The Maritime climate presents significant challenges for pavement engineers. With annual precipitation averaging 1,400 millimetres in many coastal areas and temperature fluctuations ranging from -25°C to +35°C, pavement structures must be designed to withstand extreme conditions. Key design considerations include:

• Frost penetration depths: Ranging from 1.2 to 1.8 metres across Nova Scotia, requiring adequate granular base depths

• Subgrade moisture sensitivity: Many areas feature clay-rich soils with high plasticity indices requiring stabilisation or removal

• Asphalt mix design: Performance-graded binders (typically PG 58-28 or PG 58-34) selected for regional temperature extremes

• Salt exposure: Coastal routes require consideration of chloride-induced deterioration in concrete structures

Modern pavement design methodologies, including mechanistic-empirical approaches outlined in the AASHTO Pavement ME Design Guide, allow engineers to model these complex interactions and optimise pavement structures for Atlantic Canadian conditions. Typical structural designs for high-volume routes incorporate 150-200 millimetres of hot-mix asphalt over 300-400 millimetres of granular base materials.

Geotechnical Engineering Challenges

Atlantic Canada's varied geological conditions, from the ancient Windsor Group salt deposits to the glacial till deposits common throughout the region, require thorough geotechnical investigation and analysis. Highway projects frequently encounter:

• Soft marine clays: Requiring preloading, wick drains, or deep foundation solutions

• Karst topography: Particularly in gypsum-bearing formations in central Nova Scotia

• Acid-generating slate: Present in the Meguma terrane, requiring careful material handling and disposal protocols

• Organic deposits: Peat bogs that may extend several metres in depth, necessitating removal or displacement techniques

Bridge Infrastructure: Assessment, Rehabilitation, and Replacement

Atlantic Canada's bridge inventory represents a critical component of the highway network, with Nova Scotia alone maintaining approximately 4,100 bridge structures. Many of these structures, constructed during the infrastructure expansion of the 1960s and 1970s, are now approaching or exceeding their original 50-year design lives.

Structural Assessment Methodologies

Modern bridge assessment protocols in Atlantic Canada follow the Canadian Highway Bridge Design Code (CHBDC) CSA S6 standards, incorporating:

• Visual inspection: Biennial inspections documenting condition states using standardized element-level protocols

• Non-destructive testing: Ground-penetrating radar, impact-echo testing, and half-cell potential surveys for corrosion assessment

• Load rating analysis: Determining safe load-carrying capacity using refined analysis methods

• Structural health monitoring: Instrumentation systems providing real-time performance data for critical structures

The transition to the CL-625 design truck standard, representing a 625-kilonewton gross vehicle weight, has necessitated reassessment of older bridges designed to previous loading standards. Many structures require posting restrictions or rehabilitation to accommodate current legal truck weights.

Rehabilitation and Replacement Strategies

Bridge rehabilitation in Atlantic Canada typically employs strategies tailored to the specific deterioration mechanisms present. Common rehabilitation techniques include:

• Deck overlays: Latex-modified concrete or asphalt membrane waterproofing systems extending deck service life by 15-25 years

• Cathodic protection: Impressed current or sacrificial anode systems for decks with active corrosion

• Fibre-reinforced polymer (FRP) strengthening: Carbon or glass fibre composites for structural capacity enhancement

• Bearing and expansion joint replacement: Addressing common deterioration points at movement locations

For structures beyond economical rehabilitation, accelerated bridge construction (ABC) techniques are increasingly employed to minimize traffic disruption. Prefabricated bridge elements and systems, including precast deck panels and slide-in bridge construction, can reduce on-site construction time by 50-70 percent compared to conventional methods.

Sustainable Highway Design and Environmental Considerations

Environmental sustainability has become a central consideration in Atlantic Canadian highway projects, driven by both regulatory requirements and broader commitments to reducing carbon emissions in the transportation sector.

Green Infrastructure Approaches

Modern highway design increasingly incorporates green infrastructure elements to manage stormwater, reduce environmental impacts, and enhance ecosystem connectivity. Key approaches include:

• Bioretention systems: Engineered facilities treating highway runoff before discharge to receiving waters

• Wildlife crossing structures: Underpasses and overpasses maintaining habitat connectivity, particularly important in Nova Scotia's moose management areas

• Living shorelines: Natural stabilisation techniques for coastal highway segments subject to erosion

• Low-impact development: Minimizing impervious surfaces and promoting infiltration where soil conditions permit

Material Innovation and Recycling

The highway construction industry in Atlantic Canada has embraced material recycling and innovation to improve sustainability outcomes. Reclaimed asphalt pavement (RAP) incorporation rates of 20-30 percent are now standard practice, with some projects achieving 40 percent or higher. Additional sustainable material practices include:

• Warm-mix asphalt: Reducing production temperatures by 20-40°C and associated emissions

• Recycled aggregate: Incorporating processed construction and demolition materials in granular applications

• Supplementary cementitious materials: Using slag cement and fly ash to reduce concrete carbon footprint by 20-40 percent

• Full-depth reclamation: In-place recycling of existing pavement structures with cement or asphalt stabilisation

Future Trends and Emerging Technologies

The highway engineering sector in Atlantic Canada continues to evolve with emerging technologies and changing transportation demands. Several key trends are shaping the future of highway infrastructure in the region.

Connected and Autonomous Vehicle Readiness

While fully autonomous vehicles remain years from widespread deployment, highway infrastructure must be designed with future connectivity in mind. This includes considerations for:

• Pavement markings: High-retroreflectivity markings detectable by machine vision systems

• Communication infrastructure: Right-of-way provisions for vehicle-to-infrastructure (V2I) communication equipment

• Digital mapping: High-definition survey data supporting autonomous navigation systems

• Geometric design: Consistent application of design standards to support automated driving systems

Climate Change Adaptation

Climate projections for Atlantic Canada indicate increased precipitation intensity, sea-level rise of 0.5-1.0 metres by 2100, and more frequent extreme weather events. Highway infrastructure must be designed with these projections in mind, incorporating:

• Enhanced drainage capacity: Sizing culverts and storm sewers for projected future rainfall intensities

• Coastal protection: Armour stone, sheet pile, or nature-based solutions for vulnerable coastal highway segments

• Resilient materials: Selection of materials and designs capable of withstanding increased climatic stresses

• Adaptive management: Monitoring programs identifying emerging vulnerabilities for proactive intervention

Asset Management and Strategic Investment Planning

Effective asset management has become essential for transportation agencies facing constrained budgets and ageing infrastructure. Modern asset management systems integrate condition data, deterioration modelling, and economic analysis to optimise investment decisions.

Nova Scotia's highway asset management approach incorporates pavement management systems analysing network-level condition data to identify optimal rehabilitation timing. By targeting preventive treatments before significant deterioration occurs, agencies can extend pavement service life by 5-8 years while reducing life-cycle costs by 15-25 percent compared to reactive maintenance approaches.

The integration of geographic information systems (GIS), building information modelling (BIM), and advanced analytics is transforming how highway assets are managed throughout their lifecycle. Digital twin technologies, creating virtual representations of physical infrastructure, enable simulation of various scenarios and optimised decision-making.

Partner with Atlantic Canada's Highway Infrastructure Experts

The complexities of highway infrastructure engineering in Atlantic Canada demand expertise grounded in local knowledge and technical excellence. From preliminary planning and environmental assessment through detailed design, construction administration, and asset management, successful highway projects require comprehensive engineering support tailored to Maritime conditions.

Sangster Engineering Ltd. brings decades of experience in highway infrastructure projects throughout Nova Scotia and Atlantic Canada. Our team of professional engineers understands the unique challenges of designing and maintaining transportation infrastructure in the Maritime environment, from addressing frost-susceptible soils to developing climate-resilient designs that protect public investment for generations to come.

Whether your project involves pavement rehabilitation, bridge assessment, drainage improvements, or new highway construction, we provide the technical expertise and local knowledge essential for success. Contact Sangster Engineering Ltd. today to discuss how our highway infrastructure engineering services can support your next project in Amherst, Nova Scotia, or anywhere across Atlantic Canada.

Partner with Sangster Engineering

At Sangster Engineering Ltd. in Amherst, Nova Scotia, we bring decades of engineering experience to every project. Serving clients across Atlantic Canada and beyond.

Contact us today to discuss your engineering needs.