A new four-lane divided multilane highway (two lanes in each direction) is being planned with 12-ft lanes, 6-ft shoulders on both sides, and a 50- mi/h speed limit.
One 3% downgrade is 4.5 mi long, and there will be four access points per mile. The peak-hour directional volume along this grade is estimated to consist of 1800 passenger cars, 140 large trucks, 40 buses, and 10 recreational vehicles.
If the peak-hour factor is estimated to be 0.85 and the driver population adjustment factor is expected to be 1.0, what level of service will this segment of highway operate under?