In Los Angeles, the Los Angeles Police Department (LAPD) noticed that gang violence was higher in some neighborhoods. LAPD hypothesized that this was related to rival gang fighting for territory to sell drugs. They determined that 80–90% of drive-by shootings occurred on streets near the edge of the community, which offered a quicker escape due to proximity to major roads and highways. LAPD targeted fourteen of these streets near traffic arteries, installing permanent vehicle barriers beginning in February 1990. The barriers were initially concrete, but were replaced by iron gates that could be unlocked for emergency access. All the barriers were in an area of about near Jefferson High School. In addition to vehicle barriers, ten officers patrolled the area on bicycles.
