I do not know how many times I have seen someone honking his or her horn during it because someone stopped in the middle of the road.
I do understand that different posts have different requirements.
The showing of the right hand eventually became a symbol of respect.
It is also, in some form, used all around the world.
Many historians think that the United States military salute derived from the "open hand" British Army salute that is palm down and toward the shoulder.
In the Army, any personnel in uniform are required to salute if they recognize persons entitled to the salute.
A salute is defined as "show[ing] respect and recognition to (a military superior) by assuming a prescribed position" by the Merriam-Webster Dictionary. It is said that the salute began in late Roman times when assassinations were rampant.
When the citizens wanted to see a public official, they had to advance toward the official with their right hand raised to show that they did not have a weapon.
Persons entitled to the salute include the President of the United States or Commander-in-Chief, Commissioned Officers, Warrant Officers, any Medal of Honor recipient, and Officers of friendly foreign countries.
Salutes can and should be exchanged with soldiers of the United States Navy, the Air Force, the Marine Corps, and the Coast Guard.