(Shockwave analysis): Assume the traffic flow on a highway is 1800veh/hr/lane, and the density is 14.4veh/km/lane. To reduce speeding on a section of highway, a police cruiser decides to implement a rolling slowdown, and to travel at the speed 88km/hr for 10 km. No one is allowed to pass. After the police cruiser joins, the platoon density increases to 20 veh/km/lane and flow drops. How many vehicles (per lane) will be in the platoon when the police car leaves the highway