a. Discuss the causes of shockwave b. A stream of traffic moving at a speed of 40km/h and a concentration of 20veh/km is stopped for 2mins by a herd of cattle crossing the road. After the herds departure, the vehicles began moving at a speed of 20km/h and a concentration of 60oveh/km. Assuming a jam concentration of 150veh/km, calculate i. The velocity and direction of the stopping wave ii. The length of the line of cars stopped during the 2mins period iii. The number of cars stopped during the 2mins