Is it legal for a long truck to shut down traffic?

Question

I was killing time on YouTube the other day, and came across a video of a shipping company moving a very long girder to a construction site. There were several points in the move that they had to block all traffic through an intersection (with one of the chase cars) for a few minutes in order for the truck to be able to swing around enough to make the turn.

Now, just to be clear, I wouldn't have a problem with this if I were in one of the cars that was inconvenienced for a minute. But I do want to know, is it, strictly speaking, legal? Is there something in their oversized vehicle permit (or whatever paperwork) that says "You can block the road"? Or is it simply a matter of practicality, where the police realize that they need to get the girder there somehow, and it would cost more time and money to ticket them for blocking the road than it would just to let them continue?

Answer 1

Oversize transports are known beforehand and have special permits.

The department of transportation/Federal Highway Administration provides information for oversize and overweight transports.

Permits

The Federal government does not issue permits for oversize or overweight vehicles. This is a State option.

Nondivisible Loads:

Permits may be issued by the States without regard to the axle, gross, or Federal bridge formula requirements for nondivisible vehicles or loads. Nondivisible is defined as any load or vehicle exceeding applicable length or weight limits which, if separated into smaller loads or vehicles, would:

• Compromise the intended use of the vehicle, i.e., make it unable to perform the function for which it was intended;
• Destroy the value of the load or vehicle, i.e., make it unusable for its intended purpose; or
• Require more than 8 work hours to dismantle using appropriate equipment. The applicant for a nondivisible load permit has the burden of proof as to the number of workhours required to dismantle the load.

In this case, a super-long girder has its value from being a single item, so the state is allowed to make a special permit to exceed the normal regulations on weight and size. The regulations what is needed for a permit and what the permit allows is state specific.

Typically, the permit is single-use and bound to a specific day and route. It's also not atypical for the crossings to be closed by police before the truck convoy arrives. Even without a police escort, the special permit allows them to block the road in specific circumstances, such as taking a tight turn.