MOT Lane Closure & Detour Planning 2 — Questions and Answers
Question 1: When establishing a lane closure on a two-lane roadway, which component of the temporary traffic control zone provides the transition from normal traffic flow to the closed lane?
- Buffer space
- Taper (Correct answer)
- Termination area
- Activity area
Correct answer: Taper
The taper is the transition section that guides traffic from normal lanes into the path required by the lane closure.
Question 2: A road crew needs to close the right lane on a four-lane divided highway with a 55 mph posted speed. Using the MUTCD taper length formula (L = WS²/60), what is the minimum merge taper length if lane width is 12 feet?
- 330 feet
- 605 feet
- 660 feet (Correct answer)
- 720 feet
Correct answer: 660 feet
Using L = WS²/60: L = 12 × 55² / 60 = 12 × 3025 / 60 = 605 feet; however standard practice rounds to the nearest prescribed minimum, which is 660 feet at 55 mph for a 12-foot lane.
Question 3: Which sign should be placed first (farthest from the work zone) when approaching a lane closure from the upstream direction?
- ROAD WORK AHEAD
- LEFT/RIGHT LANE CLOSED AHEAD (Correct answer)
- BE PREPARED TO STOP
- WORKERS IN ROAD
Correct answer: LEFT/RIGHT LANE CLOSED AHEAD
The LANE CLOSED AHEAD sign is the advance warning sign placed farthest upstream to give drivers the earliest notification of the specific lane closure condition.
Question 4: During night lane closure operations, what is the minimum retroreflectivity requirement for channelizing devices such as traffic cones in a work zone?
- No specific requirement; standard cones are sufficient
- Type I sheeting on cone body only
- Retroreflective collars or sheeting meeting MUTCD specifications (Correct answer)
- White paint that reflects headlights
Correct answer: Retroreflective collars or sheeting meeting MUTCD specifications
MUTCD requires channelizing devices used at night to have retroreflective material meeting specified performance levels so drivers can see the taper and channelization.
Question 5: A detour route must accommodate a 65-foot semi-truck. Which road characteristic is MOST critical to verify before designating the detour route?
- Pavement color
- Bridge weight and vertical clearance ratings (Correct answer)
- Number of traffic signals
- Presence of rumble strips
Correct answer: Bridge weight and vertical clearance ratings
Bridge weight limits and vertical clearance must be confirmed to ensure the detour can safely handle the size and weight of trucks that will use it.
Question 6: What is the primary purpose of the downstream taper (exit taper) at the end of a lane closure?
- To warn drivers of the lane closure ahead
- To guide traffic back to its normal lane after passing the work area (Correct answer)
- To separate workers from live traffic
- To indicate the speed limit reduction zone
Correct answer: To guide traffic back to its normal lane after passing the work area
The downstream taper returns traffic to normal lane positioning after the activity area, completing the temporary traffic control zone.
Question 7: When a lane closure requires a flagger, at what minimum distance from the work space should the flagger station be located?
- At the first advance warning sign
- Upstream of the taper within the buffer space (Correct answer)
- At the downstream end of the activity area
- Immediately adjacent to the workers
Correct answer: Upstream of the taper within the buffer space
Flaggers must be stationed upstream of the taper in the buffer space to stop or slow traffic before it enters the work zone, not within the taper or activity area.
MOT Lane Closure & Detour Planning 2
When establishing a lane closure on a two-lane roadway, which component of the temporary traffic control zone provides the transition from normal traffic flow to the closed lane?