MOT Nighttime Work Zone Operations 2 — Questions and Answers
Question 1: What is the minimum retroreflectivity requirement for Type III barricades used in nighttime work zones?
- 50 cd/lux/m²
- 100 cd/lux/m² (Correct answer)
- 200 cd/lux/m²
- 500 cd/lux/m²
Correct answer: 100 cd/lux/m²
MUTCD requires Type III barricades to have retroreflective sheeting meeting a minimum of 100 cd/lux/m² for nighttime visibility.
Question 2: When setting up a nighttime lane closure on a high-speed highway, how far in advance of the taper should the first warning sign typically be placed?
- 500 feet
- 1,000 feet
- 1,500 feet or more (Correct answer)
- 2,500 feet or more
Correct answer: 1,500 feet or more
On high-speed highways (55+ mph), the first advance warning sign is typically placed 1,500 feet or more before the taper, with greater distances needed at night.
Question 3: Which type of channelizing device provides the BEST nighttime visibility in a work zone?
- Standard orange cones without markings
- Cones with reflective collars (Correct answer)
- Unpainted barricades
- Painted curbs
Correct answer: Cones with reflective collars
Cones equipped with retroreflective collars or sleeves significantly improve nighttime visibility by reflecting headlight beams back to drivers.
Question 4: What does the term 'glare bomb' refer to in nighttime work zone operations?
- A flashing amber beacon
- Headlights of oncoming traffic blinding workers
- An overlit work zone that blinds approaching drivers (Correct answer)
- A high-intensity flashlight used by flaggers
Correct answer: An overlit work zone that blinds approaching drivers
A 'glare bomb' describes an excessively bright work zone where over-lighting blinds approaching drivers, increasing crash risk.
Question 5: How should flagger stations be illuminated during nighttime operations per MUTCD guidelines?
- Flaggers must carry flashlights only
- Flagger stations should be illuminated with at least 5 foot-candles of light (Correct answer)
- No specific lighting is required for flaggers
- Flaggers must stand under street lights only
Correct answer: Flagger stations should be illuminated with at least 5 foot-candles of light
MUTCD guidelines recommend flagger stations be illuminated with a minimum of 5 foot-candles so drivers can see the flagger and their signals clearly.
Question 6: What is the primary purpose of a shadow vehicle (truck-mounted attenuator) in a nighttime work zone?
- To block sunlight from workers during early morning shifts
- To absorb impact of errant vehicles and protect workers (Correct answer)
- To carry extra channelizing devices
- To provide lighting for the work area
Correct answer: To absorb impact of errant vehicles and protect workers
A shadow vehicle with a truck-mounted attenuator (TMA) is positioned to absorb impacts from errant vehicles, protecting workers in the activity area.
Question 7: At what distance should a driver typically be able to see a retroreflective sign in a nighttime work zone with proper illumination?
- 100 feet
- 200 feet
- 500 feet (Correct answer)
- 1,000 feet
Correct answer: 500 feet
Retroreflective signs in nighttime work zones should be visible at a minimum of 500 feet to give drivers adequate reaction time.
MOT Nighttime Work Zone Operations 2
What is the minimum retroreflectivity requirement for Type III barricades used in nighttime work zones?