Work Zone Planning & Design Principles Flashcards

In work zone design, what does the abbreviation 'TTC' stand for?

Answer: Temporary Traffic Control

TTC stands for Temporary Traffic Control, which encompasses all measures taken to guide road users safely through or around a work zone.

Which type of work zone taper is used to merge traffic from a closed lane into an open lane?

Answer: Merging taper

A merging taper directs traffic from a closed lane into an adjacent open lane using channelizing devices placed at an angle.

What is the recommended minimum length formula for a merging taper on roads with speeds of 45 mph or greater?

Answer: L = WS²/60

For speeds ≥45 mph, the MUTCD formula L = WS²/60 is used, where L is taper length in feet, W is offset width in feet, and S is posted speed in mph.

A 'one-lane, two-way' operation is most safely managed by a flagger when the queue length does not exceed:

Answer: 1,000 feet or sight distance limitations

Flagger-controlled one-lane operations work best when queues are short enough that flaggers can see each other or communicate; long queues may require pilot cars or signals instead.

What is the purpose of a 'shifting taper' in a work zone?

Answer: To laterally shift traffic away from the work area without reducing the number of lanes

A shifting taper moves all traffic lanes laterally to provide clearance for work activities while maintaining the same number of through lanes.

When planning a nighttime work zone, which additional design consideration is MOST important compared to daytime operations?

Answer: Enhanced lighting and retroreflective materials for visibility

Nighttime work zones require enhanced lighting for worker safety and high-retroreflectivity devices and signs so drivers can see the work zone layout in darkness.

Which of the following best describes the 'activity area' within a work zone?

Answer: The section containing the work space, traffic space, and buffer space

The activity area encompasses the work space (where workers and equipment operate), the traffic space (lanes open to vehicles), and buffer spaces separating them.