In Richmond Hill, the biggest challenge isn't just the traffic loading on Yonge Street or Highway 404—it's what lies beneath the asphalt. The town sits squarely on the Oak Ridges Moraine, a legacy of glacial retreat that left behind a complex stratigraphy of dense till, silty sands, and occasionally soft lacustrine deposits near the kettle lakes. When we assess a new subdivision or a commercial plaza expansion, we don't start with the pavement; we start with the subgrade CBR values, which can swing from below 3% in poorly drained silts to over 15% in the hard-packed Halton Till. Getting the CBR road testing data right early, before the first lift of granular base goes down, prevents the alligator cracking that plagues under-designed commercial lots after just two winter seasons. The freeze-thaw cycling here, which penetrates up to 1.2 meters during a typical Ontario winter, demands a structural number that accounts for the spring thaw weakening period, and we integrate full-depth asphalt or granular equivalency designs based on the MTO structural design method adapted for municipal standards.
A pavement is only as strong as the subgrade it rests on—in Richmond Hill's glacial terrain, that means designing for the spring thaw, not the dry summer.
