school zone(20 mph) of ¼ mile length is located on a 40 mph highway

school zone(20 mph) of ¼ mile length is located on a 40 mph highway.Stream measurements  at various sections upstream, middle of the school zone, and just downstream of the school  zone are respectively as follows: 
Approaching zone : qA = 1000 veh/hr, vA= 40mph 
Middle of zone : qB = 1100 veh/hr, vB= 20mph 
Downstream of zone: qC =1200 veh/hr, vC= 30mph 
Sketch the q-k-v curves and indicate critical values. Calculate the intensity and direction of the  shock waves created by the speed zone and the time required to disperse it?(Assume the speed zone restrictions operate for only 15 min during morning and evening periods).