[GorbachevyChase]

I designed highways. This is correct, and this is why weight restrictions exist. Noncompliance is not that much of an issue, and there are occasional permitted loads anyway when there’s a need to haul industrial equipment or unusually large objects.

The most important thing to remember about flexible, pavement lifespan is that asphaltic pavements are not designed to last forever. The asphalt binder will eventually oxidize and become brittle even with no traffic. These surfaces are meant to be consumable bearing services that last for 10 or 20 years and then have to be removed and or overlaid.

[deepsun]

Thank you. What about concrete pavements? I assume they can last longer, but I often see badly cracked concrete. Regular (expansion?) cracks also don't increase riding comfort.

[GorbachevyChase]

Welcome! Concrete pavements should (but often don’t) last much longer. They are much thicker than asphalt pavements though. The asphalt section of flexible pavement on the street by your house might only be two or 3 inches thick. Plain concrete would be no less than 6. Cracking is inevitable because concrete is brittle andhas a surprising amount of thermal expansion. The longevity of the concrete can be improved with steel reinforcement, and that’s typical for interstate pavement design. One typical pattern in Texas is to have cement stabilized soil base and an asphalt bond breaker between it and the continuously reinforced concrete pavement you see on the surface.