Speed-Density Data on Freeway A Space Mean Speed (mph) Average Density (vpm) 10 150 15 140 20 125 25 120 30 90 40 75 50 45 55 30 60 20 75 10 b Derive...

50,000lb

here are 3 lanes in the design direction (conservative design is to be used). reliability is 90%, overall standard derivation is 0.40, PSI is 1.8, and the design life is 15 years. The soil has a resilient modulus of 13, 750 psi, if the TSI is 2.5, using the AASHTO design method.

i. Determine the required structural number

ii. Determine the adequate thickness of the individual layers (asphalt surface, base, and sub-base) based on the design material of choice.