1. Pneumatic tubes are used for ______
a) Traffic counting
b) Surveying
c) Parking counts
d) Delay time
Explanation: Pneumatic tubes are used for Traffic counting. They are also used to measure speeds.
2. What is the disadvantage of Pneumatic tubes?
a) They are costly
b) They require skill
c) They count the number of axles
d) They are not portable
Explanation: The main disadvantage of Pneumatic tubes is that they count the number of axles not number of vehicles. Vehicles with multiple axles will cause five or more actuations. Therefore, manual observation is required for this method.
3. What was the first permanent detector used?
a) Inductive loop
b) Pressure plate
c) Magnetic detector
d) Magnetometer
Explanation: The first permanent detector used was Pressure plate. Two plates separated by rubber spring is connected to low voltage power source. When a vehicle moves over it, the two plates comes together completing the circuit and creating an electric pulse.
4. What is the principle used by the inductive loop?
a) Induction
b) Electromagnetic field
c) Doppler effect
d) Scattering
Explanation: The principle used by the inductive loop is Electromagnetic field. When a vehicle enters the field of loop, inductance properties of loop decreases and the presence of a vehicle is recorded.
5. What is the standard loop detector size?
a) 12ft X 12ft
b) 10ft X 10ft
c) 6ft X 6ft
d) 5ft X 5ft
Explanation: The standard loop detector size is 6ft X 6ft. And it covers only one lane. Longer loops are also available from size ranging from 6ft X 40ft to 6ft X 80ft.
6. Inductive loop directly measures ________
a) Speed of vehicles
b) Delay time
c) Passage and presence of vehicles
d) Travel time from one location to another
Explanation: Inductive loop measure’s passage and presence of vehicles. Speed and density of vehicles can be calibrated from algorithms.
7. What are the two types of magnetic detector?
a) Magnetometer and magnetic sensor
b) Speed detector and magnetic sensor
c) Magnetometer and speed detector
d) Density detector and speed detector
Explanation: The two types of magnetic detector are magnetometer and a magnetic sensor. Magnetic detectors are a type of permanent detector.
8. Which magnetic detector can measure both passage and presence of vehicles?
a) Magnetometer
b) Magnetic sensor
c) Magnetometer and Magnetic sensor
d) Speedometer
Explanation: Magnetic detector which can measure both passage and presence of vehicles is Magnetometer. Magnetic sensor can detect only passage of vehicles.
9. What is the principle upon which the magnetic detector is based on?
a) Doppler effect
b) Electromagnetic field
c) Moving metal disturbs earth’s magnetic field
d) Charles law
Explanation: The principle that magnetic detector is based on is that moving metal i.e. vehicles disturbs earth’s magnetic field. This disturbance is detected and counted.
10. Magnetic detectors are placed over roadway.
a) True
b) False
Explanation: Magnetic detectors are placed under the roadway. They are also placed under the sub-base. They are used to estimate movement and presence of vehicles. Commonly used magnetic detectors are Magnetometer and Magnetic sensor.