| The "major highways" in my city are routinely shut down for half a day or more for any and all of the following: - the President is in town, and he and the 200+ vehicles in his entourage want to go from point A to point B - a funeral for any firefighter or policeman is being held, and the funeral party wants to travel from the cathedral to the cemetery - a museum wants to move an artwork (a big hunk of stone) from a quarry to their facility, or a space shuttle orbiter from the airport to their facility (I think the orbiter only shut down city streets, not freeways) - a hockey team won their league championship, and the company that owns the team wants to hold a celebratory parade (one of our basketball teams used to do the same, back when they used to win championships) - the police department want to hold a staged "counter terrorism" exercise (complete with stunt coordinator, director, and a giant video screen scrolling the credits for the audience of VIPs) in the center of downtown mid-day on a weekday. Not to mention that emergency vehicles generally only travel a short distance, and so don't bother with the freeways unless the emergency is actually on the freeway. |
The difference is that if a resource is known to be unavailable for a time, people can plan accordingly.