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Question 2 a) The projected traffic composition for the first year of operation in interstate rural area is summarized in Table Q2(a). The percent of traffic on the design lane is 65%. The design life is 10 years, and the traffic growth rate is 4.5%. Using the information given, determine the estimated ESAL for the design lane of the expressway extension. (5 marks) Table Q2(a): Traffic Volume and Vehicle Composition Vehicle Composition Number of vehicles Passenger Cars, Pickup, & light van Single unit truck 2250 2-axle, 4 tyre 375 2-axle, 6 tyre 336 4-axle, 8 tyre 198 Semi-trailer truck 3-axle 494 4-axle 178 6-axle 119 b) Utilising the estimated ESAL in Question Q2(a), design the thicknesses of a flexible pavement layers for the proposed highway according to the AASTHO method. The following information is given: i. Initial serviceability = 4.5 ii. Terminal serviceability = 2.5 iii. Reliability = 95% iv. Standard deviation = 0.5 V. AC's Mat 68Fº= 400,000 lb/in? vi. M. of granular roadbase course =32,500 lb/in? vii. Mr of subbase course =15,500 lb/in? viii. R value of subgrade = 13 ix. Drainage coefficients, m2=m3= 0.8 The design must comply with AASHTO minimum layer thickness requirement. (10 marks) (Note: Nomograph is to be attached together with your answer script)