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Illinois Institute of Technology Department of Civil and Architectural Engineering CAE419: Introduction to Transportation Engineering and Design Midterm Exam 2 November 2, 2016 •Place your name on all sheets of the exam. •Pay close attention to the relative points assigned to each question. Proportion your time accordingly. •Read each question completely and carefully before starting work. •Please pay attention to the consistency of units in your computation. You must include units in all your answers to receive full credit. •Check that your exam contains 9 pages. Name:__________________Key_____________________
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Name:____________________________________________ 1 1.(20 points) A 3-mile six-lane freeway (three lanes in each direction) segment is on rolling terrain with 12-ft lanes, 2-ft right shoulder lateral clearance. The traffic stream consists of familiar urban commuters. A directional weekday peak-hour volume of 2,200 vehicles is observed with 700 vehicles arriving in the most congested 15-min period. The traffic stream has 10% large trucks and buses and 5% recreational vehicles. Assume a base free flow speed of 75 mph, maximum flow rate (i.e., capacity) of 2,300 pcphpl, and no interchange in this freeway segment. Determine the level of service. PHF = 2,200/(700 x 4) = fHV= 1/[1 + PT(ET-1) + PR(ER-1)] = 1/[1 + 10%(2.5-1) + 5%(2.0-1)] = fp= 1.0 vp= V/(PHF x N x fHVx fp) =2,200 / /(PHF x 3 x fHVx 1.0) = FFS = BFFS- fLW- fLC- fN- fID= 75 - 0 –1.6 –3.0 - 0 = 70.4 mph D = vp/ FFS =