San Francisco tried building some koban in the 1980s. One was at 16th and Mission, and the other was on Post St. in Japantown.[1] There was one in Chinatown, and one at the Powell/Market St. cable car turntable. Seldom were there cops in them. They just were not much more useful than cops walking around.
Larger storefront police substations have a better track record, but they're not common. They're expensive to staff. But that's not the problem. Here's what Japan's police agency thinks of their own police box system:[2]
Good security conditions are a fundamental prerequisite for the system. Although police boxes are institutions designed to secure public safety, they can only be successful in areas that are already safe. For example, in an area where terrorist attacks frequently occur, police boxes could become easy targets. It is still necessary for officers to make a lot of effort in order to defend a police box against less serious crimes such as vandalism and other attacks. A small number of officers are deployed to a large number of places under the system. Therefore, the police box system can be successful under highly secure conditions such as what Japan has.
Japan’s good security conditions have been underpinned by the police box system, and also by non-police factors such as sea-bound geographical conditions, a highly homogeneous society, group conscious culture, economic and industrial development, and strict weapons ownership control. In other words, the police box system has been able to contribute to the safety of Japan because it already had favorable conditions for maintaining public security.
Larger storefront police substations have a better track record, but they're not common. They're expensive to staff. But that's not the problem. Here's what Japan's police agency thinks of their own police box system:[2]
Good security conditions are a fundamental prerequisite for the system. Although police boxes are institutions designed to secure public safety, they can only be successful in areas that are already safe. For example, in an area where terrorist attacks frequently occur, police boxes could become easy targets. It is still necessary for officers to make a lot of effort in order to defend a police box against less serious crimes such as vandalism and other attacks. A small number of officers are deployed to a large number of places under the system. Therefore, the police box system can be successful under highly secure conditions such as what Japan has.
Japan’s good security conditions have been underpinned by the police box system, and also by non-police factors such as sea-bound geographical conditions, a highly homogeneous society, group conscious culture, economic and industrial development, and strict weapons ownership control. In other words, the police box system has been able to contribute to the safety of Japan because it already had favorable conditions for maintaining public security.
That's why it wouldn't work in the US.
[1] http://www.nytimes.com/1988/02/16/us/latest-japanese-import-... [2] https://www.npa.go.jp/english/seisaku1/JapaneseCommunityPoli...