A highway is to be constructed with a design speed of 100km/h. On one section of this highway, a +2.0% gradient of length 0.85km will be connected to a -1.5% gradient of length 1.20km. Estimate the power required for an electric vehicle of mass 2,000kg to travel from the start of the +2.0% gradient to the end of the section of road at the prescribed design speed. Take the coefficient of drag Co= 0.28, the frontal area of the vehicle A1 = 2.1m2 and air density p = 1.2256 kg/m°. Ignore the effects of vertical and horizontal curvature. [Recall Energy = Power x time) [5 marks] (b) 6 With reference to Q2(a), an equal tangent vertical crest curve will be designed to connect the grades of +2.0% and -1.5%. Determine the length of curve required to meet the minimum stopping sight distance for a driver with eye height of 1.2m and an object of height 1.0m above the road surface. (Assume a perception-reaction time of 2.5 seconds and a coefficient of friction of 0.28). [5 marks] (c) Engineers wish to estimate the capacity of a road following the introduction of a specific autonomous vehicle technology that would replace human control in certain aspects of motorway driving. If the maximum deceleration of cars ranges from 6.2 m/s? to 7.9 m/s, and the length of cars ranges from 5.0m to 70m, considering the worst case scenario, estimate the safe following headway and hence the safe capacity of a single lane of motorway traffic with a design speed of 85km/h. Assume the response time of following autonomous vehicles is 0.1s and that the safety margin after an emergency stop is 1.0m [5 marks] (d) d The inside bend of a 2-lane single carriageway of width 7.2 metres has a horizontal radius of 750m and a superelevation of 2.5%. The road crosses agiver, and the safety railings on the bridge are located 6.5 metres from the road's centre line. Calculate the mandmum speed at which vehicles can safely negotiate this bend. Assume a perception-reaction time of 2 seconds, a coefficient of forward friction (1) (also known as the adhesion coefficient) of 0.3, and a coefficient of side friction () or 0.15 [5 marks] ok