NCDOT Traffic Engineering & Control 1 — Questions and Answers
Question 1: According to NCDOT standards, what is the minimum sight distance required at a stop-controlled intersection on a road with a posted speed of 45 mph?
- 335 feet
- 415 feet (Correct answer)
- 500 feet
- 280 feet
Correct answer: 415 feet
NCDOT follows AASHTO guidelines requiring approximately 415 feet of stopping sight distance for a 45 mph posted speed at stop-controlled intersections.
Question 2: Which MUTCD-compliant sign color is used for NCDOT guide signs on the state highway system?
- Blue with white legend
- Brown with white legend
- Green with white legend (Correct answer)
- White with black legend
Correct answer: Green with white legend
MUTCD specifies green with white legend for highway guide signs indicating destinations and distances on state highway systems.
Question 3: What is the standard minimum lateral clearance from the edge of travel lane to a fixed roadside object on a primary North Carolina highway?
- 2 feet
- 6 feet (Correct answer)
- 10 feet
- 14 feet
Correct answer: 6 feet
NCDOT design standards require a minimum 6-foot lateral clearance from the edge of the travel lane to fixed objects on primary highways.
Question 4: Under NCDOT traffic signal timing guidelines, what term describes the total time for a traffic signal to complete one full cycle through all phases?
- Phase interval
- Cycle length (Correct answer)
- Offset period
- Split duration
Correct answer: Cycle length
Cycle length is the total time, in seconds, for a traffic signal to complete one full sequence of all signal phases.
Question 5: Which traffic study does NCDOT primarily require to determine if a traffic signal is warranted at an unsignalized intersection?
- Level of service analysis
- Peak hour factor study
- MUTCD warrant analysis (Correct answer)
- Gap acceptance study
Correct answer: MUTCD warrant analysis
NCDOT requires a MUTCD warrant analysis using the eight warrants defined in the Manual on Uniform Traffic Control Devices to justify signal installation.
Question 6: What is the purpose of a left-turn overlap phase in NCDOT signal design?
- Allows left turns during the opposing through green
- Provides additional green time to a left-turn movement concurrent with a non-conflicting phase (Correct answer)
- Extends pedestrian crossing time at an intersection
- Reduces cycle length by eliminating separate left-turn phases
Correct answer: Provides additional green time to a left-turn movement concurrent with a non-conflicting phase
An overlap phase grants additional green time to a movement—such as a left turn—when it can safely operate concurrently with another non-conflicting phase.
Question 7: According to NCDOT standards, pavement markings that delineate the edge of the roadway on the right side are typically what color?
- Yellow
- White (Correct answer)
- Blue
- Red
Correct answer: White
MUTCD and NCDOT standards specify white edge line markings on the right side of the roadway to delineate the boundary of the travel lane.
NCDOT Traffic Engineering & Control 1
According to NCDOT standards, what is the minimum sight distance required at a stop-controlled intersection on a road with a posted speed of 45 mph?