A multilane highway, with three lanes in each direction, operates at maximum level of service D conditions during the peak hour with an observed speed of 48.0 mi/h (with 3690 veh/h observed). The highway is on rolling terrain and the traffic stream consists of cars and some percentage of heavy vehicles. The peak-hour factor is 0.85. If heavy vehicles were banned from the highway and car traffic remained the same, what would be the LOS