This study improved on the existing work by examining these issues with a more rigorous scientific design. The researchers first examined the relationship between land-use law, the built environment, and crime using detailed block-level crime data and careful observations conducted on 205 blocks in eight different relatively high-crime areas of Los Angeles. They then analyzed the relationship between changes in land-use zones and crime in all neighborhoods in Los Angeles.
The study finds that zoning matters. An important fraction of reported crime is associated with the primary kind of zoning on a city block:
- Blocks that include both residential and commercial zoning uses exhibit less crime than blocks that are zoned for primary commercial purposes.
- Crime is lowest in blocks zoned for residential-only uses even in relatively high crime neighborhoods, suggesting that efforts to reduce crime by introducing commercial activities in residential areas are probably misguided.
- When neighborhoods across Los Angeles undergo some change in zoning, mostly toward residential uses, crime drops more than it does in neighborhoods with comparable crime trends before the zoning change occurred, suggesting the apparent crime-reducing effects of residential development.
Changing zoning to include parcels with residential uses on blocks that are otherwise zoned commercially might be a viable means of reducing crime in Los Angeles. The study also suggests that planners should recognize the crime-reducing effects of residential zoning.