1. What are the upper limit and the lower limit of the traffic volume for the installation of a traffic rotary?
a) 3000 and 500 vehicles per hour
b) 5000 and 500 vehicles per hour
c) 6000 and 500 vehicles per hour
d) 3000 and 1000 vehicles per hour
Explanation: The upper limit and the lower limit of the traffic volume for the installation of a traffic rotary is 3000 and 500 vehicles per hour. Not every location is suitable for a rotary. Rotaries are also suitable when the traffic entering from all the four approaches are comparatively equal.
2. What does macroscopic stream models represent?
a) Change in behaviour of one parameter with respect to another
b) The flow density
c) The maximum passengers the vehicle can accommodate
d) The characteristics of vehicles with respect to pedestrians
Explanation: The macroscopic stream models state how one parameter’s behavior changes according to another parameter in traffic flow. The most important relationship that this model caters to is the speed and density relation.
3. What type of relationship did Greenfield assume in the speed and density relationship?
a) Elliptical
b) Linear
c) Exponential
d) Parabolic
Explanation: The type of relationship Greenfield assumed in the speed and density relationship was a linear relationship. Speed of the vehicle tends to decline as the flow rates increases. Drivers slow down when there is higher density to maintain what they perceive to be safe operations.
4. Which of the following given options shows the correct relationship between speed and density according to Greenshield’s model?
a) v = vf + (vf/kj).k
b) v = vf – (vf/kj).k
c) v = vf / (vf/kj).k
d) v = vf * (vf/kj).k
Explanation: v = vf – (vf/kj).k is the correct relationship between speed and density according to Greenshield’s model. He assumed in his model that the speed and density have a linear relationship.
5. What is the shape of the relationship between flow and density according to Greenshield’s Model?
a) Linear
b) Parabolic
c) Elliptical
d) Exponential
Explanation: The shape of the relationship between flow and density according to Greenshield’s Model is parabolic. The flow(q) is equal to mean speed(v) multiplied to density(k).
6.According to Underwood’s Exponential Model, what is the relation between speed and density?
a) Linear
b) Parabolic
c) Elliptical
d) Exponential
Explanation: According to Underwood’s Exponential Model the relation between speed and density is exponential. This model was made to overcome the limitation of Greenberg’s Logarithmic model.
7. Which of the following given options shows the correct relationship between speed and density according to Underwood’s Exponential Model?
a) v = vf.e-k/ko
b) v = vf/e-k/ko
c) v = vf*e-k/ko
d) v = vf+e-k/ko
Explanation: v = vf.e-k/ko is the correct relationship between speed and density according to Underwood’s Exponential Model. Underwood’s Exponential Model is a macroscopic stream model.
8. What is the drawback of Underwood’s Exponential Model?
a) Cannot be used for predicting speeds at high densities
b) Cannot be used for predicting speeds at low densities
c) Cannot be used for predicting flow at high densities
d) Cannot be used for predicting mean speed at high densities
Explanation: The drawback of Underwood’s Exponential Model is that it cannot be used for predicting speeds at high densities. This is because, in this model, speed becomes zero only when the density reaches infinity.
9. What is meant by time-in-queue delay?
a) Time between a vehicle joining the end of the queue at a signalized intersection and the time it crosses the intersection
b) Delay during which the vehicles is at rest
c) Delay caused due to resistance of other traffic
d) Time between a vehicle joining the end of the queue at an unsignalized intersection and the time it crosses that intersection
Explanation: Time-in-queue delay is the time between a vehicle joining the end of the queue at a signalized intersection and the time it takes to cross the intersection. Stopped time delay is the delay during which the vehicles are at rest.
10. Why are the control delay caused?
a) Control devices
b) Speedometer
c) Traffic
d) deceleration to and acceleration from a stop to stopped time delay
Explanation: Control devices like signals cause control delay or fixed delay. Control delay includes both approach delay and time-in-queue delay. Approach delay is caused due to deceleration to and acceleration from a stop to stopped time delay.