While almost all cities have some form of barricades or fences in place in some neighborhoods, none have such an extensive plan as Dayton, Ohio. Creating ''defensible space'' as a means to making more amiable mini-neighborhoods is a national trend, says urban planner Oscar Newman.
* Miami and Fort Lauderdale, Fla., now have three neighborhoods with fenced streets.
* In early June, Hartford, Conn., put up concrete barricades on two streets near a housing project after a gang-related shooting.
* Two years ago in Sacramento, Calif.,. concrete barriers went up on two streets to stem the heavy traffic and cut into crime.
* Other cities with barricades or fences include San Diego; Gary, Ind.; Richmond, Calif.; Denver, Colo.; Fort Worth, Texas.; and St. Louis, Mo. Most are attempting to stop speeding traffic. Others want to stall the flow of drugs and crime.
Opposition is not uncommon. ''Slumlords often show up at community meetings,'' Mr. Newman says, ''and argue against the fences. They say a 'natural decline is being arrested' when they just want to buy buildings and divide them into low-income apartments.''
Several times lawyers representing families that deal in drugs have appeared at community meetings to oppose the plans, Newman says. ''They say the fences are civil rights violations, when they are trying to keep the lines of drug trafficking open.''