[deepsun]

I've heard that cars have negligible impact on roads. 99% damage comes from heavy haul trucks, especially those who violate weight restrictions.

By the way, I've never seen SCALES OPEN sign for the trucks, it's always SCALES CLOSED, or maybe I'm just extremely unlucky.

[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.

[paxys]

Well there aren’t semis driving down your neighborhood cul de sac (at least I hope not). Heavy trucks cause more damage to interstates and warehouse districts, yes, but that is what those roads are designed for. Most city roads meanwhile were never built to accommodate 9000 lb hummer tanks.

[tbrownaw]

Most road damage here appears after events of the form "it rained and then the temperature crossed freezing twice a day for a week".

[stevenwoo]

I’ve done a lot of trips on I5 from Central Valley to San Diego and those stations were open most of the time and I usually did it near holidays in November/December/January. Enforcement probably depends highly on location and amount of traffic.

[dralley]

The damage scales with weight. Cars cause less damage because they are lighter. Heavier cars still cause greater impact.

[gizmo686]

Damage scales with the 4th power of weight.

From what I can find, the standard weight limit for a truck in 20 tons per axle (less when multiple axles are close together).

In contrast, the average weight for a car is a bit under 4 tons (even for SUVs). Even a pickup truck is under 5.4 tons. Since these have 2 axles, that comes out to every class except loaded freight trucks having under 2.7 tons per axle on average. So a freight truck acting at the legal limit (without tandem axles) would be over 7.4 times as heavy per axle as a passenger pickup truck. Applying the 4th power law, this means a single maximally loaded truck causes about 3000 times (300,000%) as much damage as an average pickup truck; and 10,000 times (1,000,000%) as much as an average SUV. In contrast, the difference in damage caused by an average SUV and an average sedan is only about 40%

https://www.autoinsurance.com/guide/average-car-weight/

[ericd]

It’s extremely super linear, supposedly 4th power of axle weight. So it doesn’t make sense to argue over the relative size of mice when there are elephants around.