Traffic Signal Technician Level 1 | IMSA Certification Exam 2026-2027
Traffic Signal Technician Level 1
IMSA Certification Exam | 2026-2027 Update | 100 Questions with Verified Answers
Section 1: IMSA & Industry Fundamentals (History, Terminology, Standards)
Q1: An IMSA member is giving a presentation to new hires about the organization’s history. She states that IMSA was
originally founded in 1896 and that its primary function has always been promoting safety education within the traffic
signal and public safety industries. Which of the following best describes IMSA’s primary function?
A. Safety Education **[CORRECT]**
B. Equipment Manufacturing
C. Regulatory Enforcement
D. Municipal Budget Planning
Correct Answer: A
IMSA’s primary mission since its founding in 1896 has been safety education, providing training and certification for professionals who
install and maintain traffic signals and other public-safety systems. IMSA does not manufacture equipment, enforce regulations, or handle
municipal budgets.
Q2: A traffic signal technician is studying the history of signal devices. He learns that the very first mechanical traffic
signal was demonstrated in London. Who is credited with inventing this first mechanical traffic signal, and in what year
was it installed?
A. Lester Wire, 1912
B. William Potts, 1920
C. Garrett Morgan, 1923
D. J.P. Knight, 1868 **[CORRECT]**
Correct Answer: D
J.P. Knight installed the first mechanical traffic signal in London in 1868; it used revolving gas-lit lanterns. Lester Wire (1912), William
Potts (1920), and Garrett Morgan (1923) came later with electric and improved designs.
Q3: A city traffic engineer is reviewing signal specifications and notes that modern three-color signals include an amber
(yellow) phase between green and red. Which inventor is credited with introducing the amber light to traffic signals in
Detroit?
A. J.P. Knight
B. Lester Wire
C. William Potts **[CORRECT]**
D. Garrett Morgan
Correct Answer: C
William Potts introduced the first three-color traffic signal—adding the amber (yellow) light—in Detroit in 1920. Knight’s 1868 signal
was mechanical, Wire’s 1912 signal was two-color, and Morgan’s 1923 patent was a T-shaped hand-cranked device.
Q4: During an IMSA certification class, the instructor asks which organization publishes the National Electrical Code
(NEC). Which of the following is the correct publisher?
A. OSHA
B. IEEE
C. NFPA **[CORRECT]**
D. NEMA
Correct Answer: C
The National Electrical Code is published by the National Fire Protection Association (NFPA) as NFPA 70. OSHA enforces safety
regulations but does not publish the NEC; IEEE develops technical standards; and NEMA creates equipment standards, not the NEC.
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, Traffic Signal Technician Level 1 | IMSA Certification Exam 2026-2027
Q5: A newly hired technician is asked at a team meeting what IMSA stands for and what the organization’s chief purpose
is. Which statement most accurately describes IMSA’s primary function?
A. Safety Education **[CORRECT]**
B. Lobbying for federal infrastructure funding
C. Issuing municipal bonds for road projects
D. Designing signal hardware
Correct Answer: A
IMSA’s core purpose is safety education—training and certifying professionals in traffic signal systems, work zone safety, and related
public-safety infrastructure. IMSA is not a lobbying body, a financial institution, or a hardware design firm.
Q6: A technician preparing for the IMSA certification exam reads that the first electric traffic signal was installed in a
particular U.S. city in 1912. Who invented it, and where was it installed?
A. William Potts in Detroit
B. J.P. Knight in London
C. Garrett Morgan in Cleveland
D. Lester Wire in Salt Lake City **[CORRECT]**
Correct Answer: D
Lester Wire invented and installed the first electric traffic signal in Salt Lake City, Utah, in 1912. Potts’s three-color signal came later
(1920, Detroit); Knight’s was mechanical (1868, London); Morgan’s patent was filed in 1923 (Cleveland).
Q7: A utility worker is reviewing applicable codes before beginning a project that involves both electric supply stations
and communication lines. Which code specifically covers the installation and maintenance of these systems?
A. NEC (National Electrical Code)
B. OSHA 29 CFR 1926
C. MUTCD (Manual on Uniform Traffic Control Devices)
D. NESC (National Electrical Safety Code) **[CORRECT]**
Correct Answer: D
The National Electrical Safety Code (NESC) covers electric supply stations, overhead and underground electric lines, and communication
lines. The NEC addresses building wiring; OSHA covers workplace safety; the MUTCD covers traffic control devices on public roads.
Q8: An IMSA exam review question asks about significant patents in traffic signal history. Garrett Morgan was granted
a patent in 1923 for a traffic signal invention. What was notable about Morgan’s design?
A. It was the first to use an amber warning light
B. It was the first three-color electric signal
C. It was a T-shaped, hand-cranked mechanical signal with automatic stop-go positions **[CORRECT]**
D. It was the first signal to use LED technology
Correct Answer: C
Garrett Morgan’s 1923 patent was for a T-shaped, hand-cranked signal that could be positioned to show stop or go indications. The amber
light was introduced by William Potts in 1920; LED technology came decades later. Morgan’s contribution was significant but was not the
first three-color electric signal.
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, Traffic Signal Technician Level 1 | IMSA Certification Exam 2026-2027
Q9: A municipal inspector must verify that a new traffic signal cabinet’s internal wiring complies with the appropriate
code for safe electrical installations. Which code should the inspector reference?
A. NESC, published by IEEE
B. MUTCD, published by FHWA
C. NEC, published by NFPA as NFPA 70 **[CORRECT]**
D. OSHA 29 CFR 1910
Correct Answer: C
The NEC (NFPA 70), published by NFPA, is the primary code for safe electrical installations in buildings and equipment such as signal
cabinets. The NESC covers utility-scale power and communication lines; the MUTCD covers traffic control device placement; OSHA
sets workplace safety standards, not installation codes.
Q10: During a training session, an instructor asks: “In which U.S. city was the first electric traffic signal installed in
1912?” What is the correct answer?
A. Salt Lake City, Utah **[CORRECT]**
B. Detroit, Michigan
C. Cleveland, Ohio
D. New York, New York
Correct Answer: A
The first electric traffic signal was installed in Salt Lake City, Utah, in 1912, invented by Lester Wire. Detroit (Potts, 1920), Cleveland
(Morgan, 1923), and New York are not the correct answer for the first electric signal.
Q11: A traffic signal technician is researching industry standards and learns that one organization created the first
nationally recognized traffic signal standards in the United States. Which organization was this?
A. NFPA
B. OSHA
C. NEMA **[CORRECT]**
D. IEEE
Correct Answer: C
The National Electrical Manufacturers Association (NEMA) created the first traffic signal standards, which are still widely referenced
(e.g., NEMA TS 1 and TS 2). NFPA publishes the NEC, OSHA enforces workplace safety, and IEEE develops electrical engineering
standards but not traffic signal hardware standards.
Q12: An IMSA study group is quizzing each other on the chronological development of traffic signals. Which sequence
correctly orders these milestones from earliest to latest?
A. Morgan 1923 → Potts 1920 → Wire 1912 → Knight 1868
B. Knight 1868 → Wire 1912 → Potts 1920 → Morgan 1923 **[CORRECT]**
C. Wire 1912 → Knight 1868 → Morgan 1923 → Potts 1920
D. Knight 1868 → Potts 1920 → Wire 1912 → Morgan 1923
Correct Answer: B
The correct chronological order is: Knight’s mechanical signal (1868, London), Wire’s first electric signal (1912, Salt Lake City), Potts’s
three-color signal (1920, Detroit), and Morgan’s patented signal (1923, Cleveland). All other options place at least one milestone out of
sequence.
Section 2: Safety, PPE, & Work Zone Protocols
Page 3
Traffic Signal Technician Level 1
IMSA Certification Exam | 2026-2027 Update | 100 Questions with Verified Answers
Section 1: IMSA & Industry Fundamentals (History, Terminology, Standards)
Q1: An IMSA member is giving a presentation to new hires about the organization’s history. She states that IMSA was
originally founded in 1896 and that its primary function has always been promoting safety education within the traffic
signal and public safety industries. Which of the following best describes IMSA’s primary function?
A. Safety Education **[CORRECT]**
B. Equipment Manufacturing
C. Regulatory Enforcement
D. Municipal Budget Planning
Correct Answer: A
IMSA’s primary mission since its founding in 1896 has been safety education, providing training and certification for professionals who
install and maintain traffic signals and other public-safety systems. IMSA does not manufacture equipment, enforce regulations, or handle
municipal budgets.
Q2: A traffic signal technician is studying the history of signal devices. He learns that the very first mechanical traffic
signal was demonstrated in London. Who is credited with inventing this first mechanical traffic signal, and in what year
was it installed?
A. Lester Wire, 1912
B. William Potts, 1920
C. Garrett Morgan, 1923
D. J.P. Knight, 1868 **[CORRECT]**
Correct Answer: D
J.P. Knight installed the first mechanical traffic signal in London in 1868; it used revolving gas-lit lanterns. Lester Wire (1912), William
Potts (1920), and Garrett Morgan (1923) came later with electric and improved designs.
Q3: A city traffic engineer is reviewing signal specifications and notes that modern three-color signals include an amber
(yellow) phase between green and red. Which inventor is credited with introducing the amber light to traffic signals in
Detroit?
A. J.P. Knight
B. Lester Wire
C. William Potts **[CORRECT]**
D. Garrett Morgan
Correct Answer: C
William Potts introduced the first three-color traffic signal—adding the amber (yellow) light—in Detroit in 1920. Knight’s 1868 signal
was mechanical, Wire’s 1912 signal was two-color, and Morgan’s 1923 patent was a T-shaped hand-cranked device.
Q4: During an IMSA certification class, the instructor asks which organization publishes the National Electrical Code
(NEC). Which of the following is the correct publisher?
A. OSHA
B. IEEE
C. NFPA **[CORRECT]**
D. NEMA
Correct Answer: C
The National Electrical Code is published by the National Fire Protection Association (NFPA) as NFPA 70. OSHA enforces safety
regulations but does not publish the NEC; IEEE develops technical standards; and NEMA creates equipment standards, not the NEC.
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, Traffic Signal Technician Level 1 | IMSA Certification Exam 2026-2027
Q5: A newly hired technician is asked at a team meeting what IMSA stands for and what the organization’s chief purpose
is. Which statement most accurately describes IMSA’s primary function?
A. Safety Education **[CORRECT]**
B. Lobbying for federal infrastructure funding
C. Issuing municipal bonds for road projects
D. Designing signal hardware
Correct Answer: A
IMSA’s core purpose is safety education—training and certifying professionals in traffic signal systems, work zone safety, and related
public-safety infrastructure. IMSA is not a lobbying body, a financial institution, or a hardware design firm.
Q6: A technician preparing for the IMSA certification exam reads that the first electric traffic signal was installed in a
particular U.S. city in 1912. Who invented it, and where was it installed?
A. William Potts in Detroit
B. J.P. Knight in London
C. Garrett Morgan in Cleveland
D. Lester Wire in Salt Lake City **[CORRECT]**
Correct Answer: D
Lester Wire invented and installed the first electric traffic signal in Salt Lake City, Utah, in 1912. Potts’s three-color signal came later
(1920, Detroit); Knight’s was mechanical (1868, London); Morgan’s patent was filed in 1923 (Cleveland).
Q7: A utility worker is reviewing applicable codes before beginning a project that involves both electric supply stations
and communication lines. Which code specifically covers the installation and maintenance of these systems?
A. NEC (National Electrical Code)
B. OSHA 29 CFR 1926
C. MUTCD (Manual on Uniform Traffic Control Devices)
D. NESC (National Electrical Safety Code) **[CORRECT]**
Correct Answer: D
The National Electrical Safety Code (NESC) covers electric supply stations, overhead and underground electric lines, and communication
lines. The NEC addresses building wiring; OSHA covers workplace safety; the MUTCD covers traffic control devices on public roads.
Q8: An IMSA exam review question asks about significant patents in traffic signal history. Garrett Morgan was granted
a patent in 1923 for a traffic signal invention. What was notable about Morgan’s design?
A. It was the first to use an amber warning light
B. It was the first three-color electric signal
C. It was a T-shaped, hand-cranked mechanical signal with automatic stop-go positions **[CORRECT]**
D. It was the first signal to use LED technology
Correct Answer: C
Garrett Morgan’s 1923 patent was for a T-shaped, hand-cranked signal that could be positioned to show stop or go indications. The amber
light was introduced by William Potts in 1920; LED technology came decades later. Morgan’s contribution was significant but was not the
first three-color electric signal.
Page 2
, Traffic Signal Technician Level 1 | IMSA Certification Exam 2026-2027
Q9: A municipal inspector must verify that a new traffic signal cabinet’s internal wiring complies with the appropriate
code for safe electrical installations. Which code should the inspector reference?
A. NESC, published by IEEE
B. MUTCD, published by FHWA
C. NEC, published by NFPA as NFPA 70 **[CORRECT]**
D. OSHA 29 CFR 1910
Correct Answer: C
The NEC (NFPA 70), published by NFPA, is the primary code for safe electrical installations in buildings and equipment such as signal
cabinets. The NESC covers utility-scale power and communication lines; the MUTCD covers traffic control device placement; OSHA
sets workplace safety standards, not installation codes.
Q10: During a training session, an instructor asks: “In which U.S. city was the first electric traffic signal installed in
1912?” What is the correct answer?
A. Salt Lake City, Utah **[CORRECT]**
B. Detroit, Michigan
C. Cleveland, Ohio
D. New York, New York
Correct Answer: A
The first electric traffic signal was installed in Salt Lake City, Utah, in 1912, invented by Lester Wire. Detroit (Potts, 1920), Cleveland
(Morgan, 1923), and New York are not the correct answer for the first electric signal.
Q11: A traffic signal technician is researching industry standards and learns that one organization created the first
nationally recognized traffic signal standards in the United States. Which organization was this?
A. NFPA
B. OSHA
C. NEMA **[CORRECT]**
D. IEEE
Correct Answer: C
The National Electrical Manufacturers Association (NEMA) created the first traffic signal standards, which are still widely referenced
(e.g., NEMA TS 1 and TS 2). NFPA publishes the NEC, OSHA enforces workplace safety, and IEEE develops electrical engineering
standards but not traffic signal hardware standards.
Q12: An IMSA study group is quizzing each other on the chronological development of traffic signals. Which sequence
correctly orders these milestones from earliest to latest?
A. Morgan 1923 → Potts 1920 → Wire 1912 → Knight 1868
B. Knight 1868 → Wire 1912 → Potts 1920 → Morgan 1923 **[CORRECT]**
C. Wire 1912 → Knight 1868 → Morgan 1923 → Potts 1920
D. Knight 1868 → Potts 1920 → Wire 1912 → Morgan 1923
Correct Answer: B
The correct chronological order is: Knight’s mechanical signal (1868, London), Wire’s first electric signal (1912, Salt Lake City), Potts’s
three-color signal (1920, Detroit), and Morgan’s patented signal (1923, Cleveland). All other options place at least one milestone out of
sequence.
Section 2: Safety, PPE, & Work Zone Protocols
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