MOT Lane Closure & Detour Planning 4 — Questions and Answers
Question 1: A temporary road closure requires pedestrian traffic to be maintained. Which requirement must the pedestrian detour path meet per ADA and MUTCD guidelines?
- It must be unpaved to slow pedestrian speed near the work zone
- It must be accessible, detectable, and maintain a minimum 60-inch clear width (Correct answer)
- It may be redirected onto the closed roadway if cones are present
- Pedestrian detours are optional for short-term closures under 3 days
Correct answer: It must be accessible, detectable, and maintain a minimum 60-inch clear width
ADA requires temporary pedestrian routes to be accessible to people with disabilities, including detectable edges and a minimum 60-inch width to allow wheelchair passage.
Question 2: What is the recommended maximum length for a two-lane, two-way flagging operation (one-lane alternating traffic) without additional traffic control measures?
- 500 feet
- 1,000 feet (Correct answer)
- 2,000 feet
- No maximum is specified
Correct answer: 1,000 feet
MUTCD recommends that single-lane alternating flagging operations generally should not exceed about 1,000 feet to keep queue lengths manageable and flagger communication feasible.
Question 3: When a lane closure on an interstate creates queues extending beyond the advance warning signs, what is the FIRST corrective action that should be taken?
- Remove one row of cones to open partial access
- Deploy additional advance warning signs or portable changeable message signs further upstream (Correct answer)
- Discontinue work immediately and remove all devices
- Reduce the number of workers to speed up the job
Correct answer: Deploy additional advance warning signs or portable changeable message signs further upstream
Extending advance warning upstream with additional signs or CMSs gives drivers earlier warning of the queue and helps prevent rear-end crashes.
Question 4: What information must a Traffic Control Plan (TCP) for a complex lane closure typically include?
- Contractor's insurance policy number and bond details
- A scale drawing showing device placement, sign locations, and spacing distances (Correct answer)
- A list of subcontractors' phone numbers
- The project budget and payment schedule
Correct answer: A scale drawing showing device placement, sign locations, and spacing distances
A TCP must include a scaled drawing with the location, type, and spacing of all signs, channelizing devices, and other TTC measures so field crews can implement it accurately.
Question 5: During a lane closure, a motorist drives through the channelizing devices and enters the work zone. What should workers do FIRST?
- Attempt to stop the vehicle by standing in its path
- Move to a safe escape route and alert the flagger or supervisor immediately (Correct answer)
- Continue working since the driver will likely self-correct
- Call 911 before taking any other action
Correct answer: Move to a safe escape route and alert the flagger or supervisor immediately
Workers must immediately move to pre-planned escape routes to avoid being struck, then alert the flagger and supervisor so traffic can be stopped.
Question 6: Which factor determines the required spacing between advance warning signs for a lane closure?
- The contractor's preference
- The posted or operating speed of the roadway (Correct answer)
- The time of day the closure occurs
- The color of the signs being used
Correct answer: The posted or operating speed of the roadway
MUTCD sign spacing tables are based on posted or 85th-percentile operating speed, because faster traffic requires greater distances to read and respond to signs.
Question 7: A detour is posted that routes heavy trucks over a county road with a posted 15-ton weight limit. The project involves regular concrete mixer trucks exceeding 20 tons. What must be done?
- Post advisory signs asking trucks to drive slowly over the bridge
- Identify and designate an alternate detour route that meets the load requirements (Correct answer)
- Allow the trucks to use the county road since detour postings override weight limits
- Reduce the concrete mixer load to under 15 tons for each trip
Correct answer: Identify and designate an alternate detour route that meets the load requirements
Using a route that cannot legally carry the project's equipment is unsafe and potentially illegal; a compliant alternate route must be found and properly signed.
MOT Lane Closure & Detour Planning 4
A temporary road closure requires pedestrian traffic to be maintained.
Which requirement must the pedestrian detour path meet per ADA and MUTCD guidelines?