It varies from country to country, and from state to state within the US. I'd start with your state's vehicle & traffic law for maximum axle weights. Your state government's website may have it on line. Otherwise check with the department of motor vehicles.
Also, check with your city sanitation department. I've heard that two-axle garbage trucks are often overweight on the rear axles.
I'm a traffic engineer, so I'm not really up to spec on pavement design, but look for "ESAL's" - equivalent single axle loads. Your state DOT's design manual may be another place to look.