An axle weight study on a section of highway gave the following data on axle load distribution. Determine the truck factor for this section of highway. Assume SN = 4 and p, = 2.5. Axle Load Group: Single (1,000 lb) No. of Axles per 1,000 Vehicles 689 Axle Load Group: Tandem (1,000 lb) No. of Axles per 1,000 Vehicles 781 487 487 4 7 0 6 10 10 14 14 14 18 20 20 22 24 26 truck factor= 0.485346 X 154 154 59 41 43 7 4 3 4 10 16 22 22 28 32 34 36 38 40 10 18 234 174 174 110 118 156 155 199 64 64 31 12 4 1

The predicted traffic mix of a proposed four-lane urban non-interstate freeway is as follows. Passenger cars = 78% Single-unit trucks: 2-axle, 5,000 lb/axle = 12% 2-axle, 9,000 lb/axle = 4% 3-axle or more, 23,000 lb/axle = 3% Tractor semitrailers and combinations: 3-axle, 20,000 lb/axle = 3% The projected AADT during the first year of operation is 3,900 (both directions). If the traffic growth rate is estimated at 3 percent and the CBR of the subgrade is 7.5, determine the depth of a full-asphalt pavement (in inches) using the AASHTO method and n = 20 years. The resilient modulus of the asphalt (EAC) is 320,000 lb/in². Assume m, for the subgrade is 1 and the percent of traffic on the design lane is 42 percent, pt = 2.5, and SN = 4. Use a reliability level of 90 percent, a standard deviation of 0.45, and a design serviceability loss of 2.0. Assume the design lane factor f is 0.42. (Use single-axle load equivalency factors for 2-axle vehicles and tandem-axle load equivalency factors for…

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