Question

Solve and show how to calculate:

Table 1 Shows the 15 minutes counts that have been recorded for number of car on the given highway 8.30-8.45p.m 8.45-9.00 p.m 9.00-9.15p.m. 1000 900 1400 1300 9.15-9.30p.m. Determine Peak Hour Factor (PHF). a) (5 marks) b) The hourly volume for a similar facility is found to be equal to 7000 vehicle/hour Determine the design volume for the facility. (5 marks) c) Calculate Passenger Car Unit (PCU) and Level of Service (LOS) of this road by assuming data given is car, dual carriageway and capacity for car is 5000 veh/hrs/lane. Give your comments on the Level of Service (LOS) of the highway. (10 marks)

Answer 1

a)

Peak Hour Factor(PHF)= Hourly volume/(4 x Max 15 Min Volume within the hour)

Here, Hourly volume= 1000 + 900 + 1400 + 1300 = 4600 vehicles

Max 15 Min Volume= 1400 vehicles

So, PHF= 4600/(4 x 1400)= 0.8214

b)

Hourly volume= 7000 vehicles

PHF= 0.821

Design Volume= Hourly Volume/PHF= 7000/ 0.8214= 8522 vehicles

c)

PCU= Design Volume x PHF

So, PCU= 5000 X 0.8214= 4107

Further, PHF is 0.8214 which lies between 0.75 and 0.85, the Level of Service shall be D. This represents Medium flow, ie the traffic flow is neither a very free flow nor a a very congested flow.