On the two lane carriageways, roadworks restrict the width of both traffic lanes, generating a bottleneck to the traffic flow. the maxi mu m flow per lane on the unobstructed carriageway is 2100 vehicles per hour whilst on the section under repairing tile maxi mu m flow per lane reduces to 1200 vehicles per hour. when stationary, vehicles are spaced at average distance headway of 6 m. it may be assumed that there is a linear relationship between speed and density. when live traffic flow approaching the roadworks is 3,500 vehicles per hour, calculate: the speed of the traffic system a considerable distance in advance of the bottleneck: the speed of the traffic stream immediately before the commencement of the bottleneck, and the speed of the shockwave foamed by the bottleneck.