Question

1. A horizontal curve on a two-lane highway is designed with a 2000 ft radius, 12 ft lanes, and 60mph design speed. Determine the distance that must be cleared from the inside edge of the inside lane to provide a sufficient stopping sight distance.

2, A flexible pavement is constructed with 102 mm (4 inches) of hot mix asphalt (HMA) wearing surface, 203 mm (8 inches) of emulsion/aggregate-bituminous base, and 203 mm (8 inches) of crushed stone subbase. The subgrade has a soil resilient modulus of 68,950 kPa (10,000 lb/in2), and M2 and M3 are equal to 1.0 for the materials in the pavement structure. The overall standard deviation is 0.5, the initial PSI is 4.5, and the TSI is 2.5. The daily traffic has 1080 89.0-kN (20-kip) single axles, 400 106.8-kN (24-kip) single axles, and 680 177.9-kN (40-kip) tandem axles. How many years would you estimate this 85% confident that your estimate was not too high, and if you wanted to be 95% confident that your estimate was not too high?

Answer 1