IMSA Traffic Signal Technician III Exam
V2 | Level III | System Design, Complex
Operations, and Specialized Traffic
Control Technologies | Q&A with Rationale
1. Which NTCIP standard specifically defines the object definitions for Actuated Traffic Signal
Controller (ASC) units?
A. NTCIP 1103
B. NTCIP 1201
C. NTCIP 2301
D. NTCIP 1202
Correct Answer: D
Rationale: NTCIP 1202 is the specific standard for object definitions regarding actuated
traffic signal controllers. While 1201 defines global objects, 1202 provides the data
structures necessary for interoperability between different manufacturers’ controllers.
This allows a central system to manage various controller brands using a unified language.
2. In a NEMA TS2 Type 1 cabinet, what is the primary communication method between the
controller and the Bus Interface Units (BIUs)?
A. Hard-wired A-B-C connectors
B. SDLC (Synchronous Data Link Control)
,C. Ethernet Cat6
D. Fiber Optic Patch Cables
Correct Answer: B
Rationale: The NEMA TS2 Type 1 architecture utilizes a high-speed SDLC serial bus for
communication between the controller and peripheral devices like BIUs and the MMU. This
replaces the bulky wiring harnesses found in older TS1 or TS2 Type 2 designs. It
significantly reduces the physical complexity of the cabinet and improves diagnostic
capabilities.
3. When designing a fiber optic network, what is the maximum acceptable loss typically
allowed for a single fusion splice?
A. 0.50 dB
B. 0.05 dB
C. 1.00 dB
D. 3.00 dB
Correct Answer: B
Rationale: Modern fusion splicers are expected to achieve losses of 0.05 dB or less per
splice. This low loss is critical for maintaining the overall optical power budget of a long-
distance traffic system network. Exceeding this value usually indicates a poor alignment or
contamination at the splice point.
, 4. In wireless traffic communication, what does the ‘Fresnel Zone’ represent?
A. The range of the radio frequency
B. The vertical height of the antenna mast
C. An elliptical area around the line-of-sight path
D. The degree of signal attenuation due to rain
Correct Answer: C
Rationale: The Fresnel Zone is an elliptical region surrounding the direct line-of-sight path
between two wireless antennas. Obstructions within this zone can cause signal
interference or phase cancellation even if the visual line-of-sight is clear. Engineers must
ensure at least 60 to 80 percent of this zone is free of obstacles for reliable data
transmission.
5. Which Ethernet layer functionality is required to segregate traffic signal data from public
Wi-Fi on the same physical fiber backbone?
A. Physical Layer (Layer 1)
B. VLAN (Virtual Local Area Network)
C. STP (Spanning Tree Protocol)
D. DHCP Server
Correct Answer: B
V2 | Level III | System Design, Complex
Operations, and Specialized Traffic
Control Technologies | Q&A with Rationale
1. Which NTCIP standard specifically defines the object definitions for Actuated Traffic Signal
Controller (ASC) units?
A. NTCIP 1103
B. NTCIP 1201
C. NTCIP 2301
D. NTCIP 1202
Correct Answer: D
Rationale: NTCIP 1202 is the specific standard for object definitions regarding actuated
traffic signal controllers. While 1201 defines global objects, 1202 provides the data
structures necessary for interoperability between different manufacturers’ controllers.
This allows a central system to manage various controller brands using a unified language.
2. In a NEMA TS2 Type 1 cabinet, what is the primary communication method between the
controller and the Bus Interface Units (BIUs)?
A. Hard-wired A-B-C connectors
B. SDLC (Synchronous Data Link Control)
,C. Ethernet Cat6
D. Fiber Optic Patch Cables
Correct Answer: B
Rationale: The NEMA TS2 Type 1 architecture utilizes a high-speed SDLC serial bus for
communication between the controller and peripheral devices like BIUs and the MMU. This
replaces the bulky wiring harnesses found in older TS1 or TS2 Type 2 designs. It
significantly reduces the physical complexity of the cabinet and improves diagnostic
capabilities.
3. When designing a fiber optic network, what is the maximum acceptable loss typically
allowed for a single fusion splice?
A. 0.50 dB
B. 0.05 dB
C. 1.00 dB
D. 3.00 dB
Correct Answer: B
Rationale: Modern fusion splicers are expected to achieve losses of 0.05 dB or less per
splice. This low loss is critical for maintaining the overall optical power budget of a long-
distance traffic system network. Exceeding this value usually indicates a poor alignment or
contamination at the splice point.
, 4. In wireless traffic communication, what does the ‘Fresnel Zone’ represent?
A. The range of the radio frequency
B. The vertical height of the antenna mast
C. An elliptical area around the line-of-sight path
D. The degree of signal attenuation due to rain
Correct Answer: C
Rationale: The Fresnel Zone is an elliptical region surrounding the direct line-of-sight path
between two wireless antennas. Obstructions within this zone can cause signal
interference or phase cancellation even if the visual line-of-sight is clear. Engineers must
ensure at least 60 to 80 percent of this zone is free of obstacles for reliable data
transmission.
5. Which Ethernet layer functionality is required to segregate traffic signal data from public
Wi-Fi on the same physical fiber backbone?
A. Physical Layer (Layer 1)
B. VLAN (Virtual Local Area Network)
C. STP (Spanning Tree Protocol)
D. DHCP Server
Correct Answer: B
