Outside of the United States, it's fairly common for police officers to be unarmed under routine circumstances. English police, for example, do not usually carry firearms on their persons (unless you are really tetchy and count the c.s spray as a firearm). There are "armed response units" where sidearms and automatic rifles are carried in the patrol vehicle, but they are kept under lock and key and brought out only when the situation requires it (unfortunately, there are more "situations" all the time).
Most U.S. law enforcement officers are armed on a regular basis, and most cops would not think of going to work unarmed. Still, there are a few specialized, "proprietary" law enforcement agencies who work unarmed. These are most often found at schools, colleges, and hospitals. These are, by far, the exception.
Most law enforcement officers in the United States may also carry their firearms concealed on their persons when off duty. This is not the case in most foreign countries. Most U.S. officers are encouraged to carry their firearms when off duty and not consuming alcohol, but very few are required to do so.
450 police departments
According to Wikipedia, there are 131 city police departments in Oregon.
There are a total of 141 police departments in the state of Florida. The largest of those is the Miami-Dade Police Department.
Police chief.
No. Many books and movies portray actual police departments.
contrasting the roles and functions of municipal and county police departments
Most police departments do post job opportunities online. Job listings for police departments can typically be found on the city's website and include requirements of the position and instructions for how to apply.
More information about a police academy may be obtained by contacting local police departments. Local police departments will have information about training requirements.
Not all police departments are the same. Some departments let ranks as low as corporals become detectives, while some departments only allow lieutenants and captains. Regarding police, I have no idea what a "level" is
No numbers are available on the percentage of police departments that use Harley Davidson motorcycles, but Harley Davidson is the leading brand for American police departments. BMW is the second most popular.
Transparency by police departments was encouraged. Most police departments hold community meetings where they explain their role to the community, and answer questions.
Many, if not all, US police Departments render gun salutes at funerals. This is not something reserved strictly for the military. Police render service, at risk of their own lives, just as military service members do.