Hello to all. This is my first post, so please be gentle.
I worked the highways for 20 years, but certainly don’t consider myself an expert.
When a State contracts with a company to do work on a specified area, that company takes over that area for the duration of the contract. That company must adhere to several safety standards as part of the contract, and one of those standards is proper construction markings (See link in above post).
Most contractors sub out this portion of the job to companies who specialize in marking highway construction zones. This subcontractor usually brings a full crew out and sets up the entire zone at the start of the project, and then leaves a smaller crew on site to maintain the markings.
Construction usually starts at one end of the zone, and proceeds to the other. Actual construction usually is only taking place in a small part of the zone, although support equipment may be transversing anywhere at any time.
Construction may not operate 24 hours a day/ 7 days a week, and is also sometimes delayed for for things like weather and material suppliers.
What this means is many times you will drive through a zone without work taking place. The speed limits stay reduced and lanes remain closed because it’s too big of job to repeatedly adjust the zone for no activity.
The state and the contractor know the zones cause delays and hassles, but most do the best they can to assure nice roadways.