Traffic Engineering & Control Flashcards

In North Carolina, what minimum length of deceleration taper is typically required for a right-turn lane on a rural state highway with a 55 mph speed limit?

Answer: 290 feet

NCDOT guidelines based on AASHTO require approximately 290 feet of deceleration taper length for a right-turn lane where approach speed is 55 mph on a rural highway.

What does a double yellow center line on a North Carolina two-lane highway indicate?

Answer: No passing is permitted for traffic in either direction

A double solid yellow center line prohibits passing in both directions of travel due to restricted sight distance or other hazardous conditions.

NCDOT's functional classification system divides roads into three principal categories. Which category includes interstates and expressways serving the highest level of mobility?

Answer: Arterial roads

Arterials—including principal arterials such as interstates—are designed primarily for mobility and carry the highest traffic volumes over longer distances.

Which NCDOT standard governs the placement and height of overhead guide signs on interstate highways?

Answer: MUTCD with NCDOT supplemental guidance

NCDOT uses the MUTCD as the primary standard for sign placement and height, supplemented by NCDOT-specific guidance for state conditions.

What is the primary purpose of an all-red clearance interval in a traffic signal cycle?

Answer: To clear vehicles that were legally in the intersection during the yellow phase before conflicting movements begin

The all-red clearance interval holds all movements at red to allow vehicles that entered during the yellow phase to clear the intersection before conflicting traffic receives a green indication.

When NCDOT performs a traffic impact analysis (TIA) review for a new development, what threshold of generated trips typically triggers the requirement for a full TIA in North Carolina?

Answer: 100 new trips in the peak hour

NCDOT generally requires a full Traffic Impact Analysis when a proposed development is expected to generate 100 or more new peak-hour trips to the highway system.

According to NCDOT standards, which pavement marking is used to separate opposing lanes of traffic on an undivided highway where passing is permitted under safe conditions?

Answer: Single broken yellow line

A single broken yellow center line indicates that passing is permitted in both directions when sight distance and conditions allow, as specified by the MUTCD adopted by NCDOT.