Traffic Engineering Quiz on “Traffic Volume Studies – Passenger Car Unit (PCU)”.

1. What is Passenger Car Unit used for?

a) to evaluate the traffic-flow rate on a highway

b) to record the number of passengers in each car

c) to record the number of passengers in each section of road

d) to evaluate the density of passengers

Answer: a

Clarification: Passenger Car Unit used to evaluate the traffic-flow rate on a highway. Passenger Car Unit is also generally known as passenger car equivalent. PCU is a metric used in transportation engineering.

2. What is the Passenger Car Unit (PCU) value of a motorcycle?

a) 1

b) 0.5

c) 0.2

d) 0.3

Answer: b

Clarification: The Passenger Car Unit (PCU) value of a motorcycle is 0.5. 1 and 0.2 are the Passenger Car Unit values of car and bicycle respectively.

3. What is the unit of highway capacity?

a) Veh/hr

b) PCU/hr

c) Veh/hr/section of road

d) PCU/section of road

Answer: b

Clarification: PCU/hr is the unit of highway capacity. Highway Capacity is the maximum traffic flow that can be accommodated in a highway during a given time period under existing roadway, traffic and control conditions.

4. Which of the following is not a factor affecting PCU?

a) Vehicles characteristic

b) Traffic stream characteristic

c) Roadway characteristic

d) Design characteristic

Answer: d

Clarification: Design characteristic is not a factor affecting PCU. Vehicles characteristic, traffic stream characteristic, roadway characteristic, and regulation and control of traffic are some the factors affecting PCU.

5. PCU value is the fraction of capacity of a road where there are passenger cars only to the ______

a) capacity of the same road when there are vehicles of that class

b) capacity of a different road when there are vehicles of that class

c) capacity of the same road when there are vehicles of a different class

d) capacity of the different road when there are vehicles of a different class

Answer: a

Clarification: PCU value is the fraction of capacity of a road where there are passenger cars only to the capacity of the same road when there are vehicles of that class. PCU is the measure of space required by the vehicle class compared to passenger cars.

6. Passenger Car Unit is an estimate of the impact that a mode of transport has on ______

a) traffic system

b) traffic variables

c) traffic signals

d) design

Answer: b

Clarification: Passenger Car Unit (PCU) is an estimate of the impact that a mode of transport has on traffic variables. Traffic variables are speed, density, headway, etc.

7. Which of the following method is used to determine PCU?

a) Multiple linear regression method

b) Average speed method

c) Spot speed method

d) Elevated observation method

Answer: a

Clarification: Multiple linear regression method is used to determine the Passenger Car Unit (PCU). Average speed method, Spot speed method, and Elevated observation method are used to determine travel time and delay studies.

8. Which method represents the speed of a traffic stream as a function of the number of variables?

a) Modified Density Method

b) Multiple linear regression method

c) Headway method

d) Chandra’s method

Answer: b

Clarification: The method that represents the speed of a traffic stream as a function of the number of variables is Multiple linear regression method. The PCU is calculated using the below formula,

En = Cn/C1,

En = PCU for a vehicle type n,

Cn = speed reduction coefficient for vehicle type n,

C1 = speed reduction coefficient for passenger cars.

9. How many factors does Chandra’s method to determine PCU depends on?

a) 1

b) 3

c) 2

d) 5

Answer: c

Clarification: Chandra’s method used to determine PCU depends on 2 factors and they are the velocity of vehicle type and its projected rectangular area to calculate the PCU value.

10. Which of the following methods to determine PCU can only be applied in India?

a) Multiple linear regression method

b) Chandra’s method

c) Headway method

d) Modified Density Method

Answer: b

Clarification: Chandra’s method is the only method to determine Passenger Car Unit (PCU) that can be applied to Indian heterogeneous roads. Other methods are suitable for developed countries having homogeneous traffic conditions.

11. Headway method is most suited on which terrain?

a) level terrain

b) mountainous region

c) hilly terrain

d) desert

Answer: a

Clarification: Headway method is most suited to determine Passenger Car Units (PCUs) on level terrain. They are suitable when level of service (LOS) is low.

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