Highway Design Principles in Alberta for Classification, Traffic Forecasts and Design Speed

Every highway geometric design starts with a few foundational decisions: what role the road plays in the network, how much traffic it will carry over its design life, and what speed its geometry must support. This course explains how provincial highways in Alberta are classified through the National Highway System (NHS), the four-level service classification and the three-letter functional classification, and how these systems relate to one another. It also covers the special designations for high load corridors and long combination vehicle (LCV) routes, and the typical design life assigned to pavements, intersections, alignment, bridges and access management planning.

The course then works through the traffic statistics that drive design, including annual average daily traffic (AADT), the 100th highest hour design hourly volume (DHV), K factors, directional split, linear traffic growth rates, and a step-by-step method for factoring short-duration intersection counts. It introduces benefit cost analysis, highway capacity and level of service (LOS) targets, width selection for two-lane undivided highways, and the factors that govern design speed selection. It closes with how design designations are built and applied, rural and urban design parameters, transition segments and hybrid roadways, design exceptions, environmental authorizations and option selection. It suits highway designers, transportation planners and reviewers working on provincial highway projects.

What Will Be Covered:

• The National Highway System, the four service classification levels and the rural and urban functional classification codes

• How the classification systems relate, including mobility versus access and adjacent land use context

• High load corridors, oversize vehicles and long combination vehicle (LCV) routes

• Design life for pavements, intersections, geometry, bridges and access management

• Annual average daily traffic (AADT), design hourly volume (DHV), K factor, directional split and linear traffic growth rate calculations

• Factoring 12-hour and 24-hour intersection counts against automated traffic recorder data, with a worked example

• Benefit cost analysis inputs, discount rate, road user costs and interpretation of results

• Level of service (LOS) measures, LOS targets by service classification and options to improve LOS or manage demand

• Design speed selection, operating speed and adapting design speed to constraints

• Design designation codes, rural and urban design parameters, transition segments, hybrid roadways, design exceptions and environmental considerations