Matthew Russotto with
If you're interested in finding the pressure that the vehicle puts on the road, you can use a pocket tool: a tire pressure gage. Ignoring the slight effect of tire sidewall stiffness, if you have (say) 35 psi in your tires, your vehicle applies 35 psi to the pavement under each tire. This is true whether you have one wheel, four wheels or sixteen. How could it be otherwise?
Multiple axles primarily benefit the truck's structure, plus help the truck meet detail requirements for safe loads on bridges. See for a little on this.
It may be that adding a load bearing axle can reduce pressure on the highway substrate, down at a depth of several feet, and this might have some benefit for the highway. But any such effect goes away at any "normal" vehicle weight. It's obviously no issue with cars; Hummers aren't required to have multiple axles. It's clearly no issue with bikes, where the total weight is so low that the pressure field dissipates just a few inches down into the asphalt.
Again, if this were not so, you'd see regulations against wearing high heels in crosswalks; or alternately, you'd see evidence of severe crosswalk damage due to stylish women.
You can prove me wrong by providing photos of crosswalks crumbled by high heeled shoes. Or sections of roadways showing damage that is clearly due to wear caused by bicycles, not other vehicles.
- Frank Krygowski
