How does the AASHTO pavement design method estimate the structural number or equivalent thickness?

How does the AASHTO pavement design method estimate the structural number or equivalent thickness?

• A. It uses empirical relations among ESALs, layer coefficients, and structural number to predict performance and life.
• B. It uses random numbers.
• C. It only considers material strength.
• D. It doesn't account for traffic.

Answer: (B)