a four-lane divided suburban multilane highway is being planned with 12-ft lanes,6-ft shoulders on both sides,and a 50 mph speed limit. one 3% downgrade is 4.5 mi. long and there will be 4 access points per mile . the peak-hour directional volume among this grade is estimated to consist of 1800 passenger cars, 140 large trucks,40 buses,and 10 recreation vehicles .if the peak-hour factor is estimated to be 0.85, what level of service will this section of high-way operate under?