The Police Station is a building type in Pharaoh.
Police stations send policemen patrolling the streets, who reduce the likelihood of criminals spawning from the neighbors they patrol. In this capacity, they perform an identical service to that of magistrates from Courthouses. However, policemen also have the ability to stop and kill criminals that do end up on the streets, while magistrates do not.
Crime emerges as a response to poor city sentiment. Having good city sentiment (by providing adequate food, water, fair taxes and wages, enough jobs etc.) practically removes citywide risk of crime, and the necessity of police stations with it. However, police stations are small, cheap, and an easy way to keep crime down in neighborhoods where crime is a problem. That being said, a city with high sentiment benefits little from police stations, as they are not required for housing evolution at all.
Policemen are somewhat tougher than regular walkers, and can fight off minor threats such as hyenas. Building police stations in areas troubled by packs of hyenas can help reduce walker mortality.
If an enemy army invades the city, nearby police stations can spawn policemen to fight the invaders. Although they are far less effective at fighting invaders than professional soldiers, they are certainly better than nothing, and can be trained en masse in case the standing army is inadequate. Because they seek out and destroy invaders, they are shown in the "City Defenses" overview. Other "Tough" non-army walkers, such as lumberjacks, are not shown under the city defenses screen. Although enough lumberjacks can defeat an invader, the lumberjacks do not actively attack enemys and only fights invaders when they get attacked by attacking combatants.
Police stations are prone to fire. They are slightly undesirable to live close to (further incentive to only build them where necessary).
Police Stations versus CourthousesEdit
For the purposes of reducing crime, the two building types serve an identical function; there are few, if any, cases where both buildings are warranted in the same area. While both buildings serve to reduce the likelihood of crime occurring in an area, police stations and courthouses have some key differences in how they function. Police stations are cheaper, smaller, and require fewer employees to staff than courthouses. In addition, courthouses house some of the city's wealth, and are thus prone to being robbed. Finally, constables can apprehend criminals and fight off wild animals and invaders, while magistrates are powerless to do so. Police stations are thus best used to look after poorer, more dangerous areas of the city.
Courthouses, on the other hand, are required to evolve housing. They are thus essential for higher-level residential areas (although not at all required for slums). They also have a positive impact on desirability.