Most jails in America are traditional in design. These jails, also referred to as having the linear design, have a long history dating back to the time of the Walnut Street Jail in Philadelphia. Traditional jails house inmates in cells situated along corridors. The staff must monitor inmates by walking the corridors in front of each cell block. This design type is often referred to as intermittent surveillance design. When staff are not present in the corridors, the inmates enjoy a free rein in their cells. Thus, the staff cannot monitor all of the inmates in a housing unit at one time; they can provide only what is referred to as intermittent surveillance.
“Second-generation” is the term given to jails that have remote or indirect surveillance of inmates. This design has been put into use in many areas and is, in many cases, the design used for new facilities. Under the remote design, cells are situated around a central dayroom, and jail personnel occupy a secure control room that overlooks the dayroom and the individual cells. While they have a number of design improvements over traditional jails, these second-generation jails often limit the verbal interactions between inmates and jail personnel.
Communication between inmates and jail personnel is frequently undertaken through an intercom. While the inmates are more closely monitored in second-generation jails than in traditional jails, most such jails still employ high-security fixtures, furnishings, and finishes.
The design of new-generation jails began with an effort by the U.S. Bureau of Prisons in the mid-1960s. The government commissioned three architectural firms to design three new federal jail facilities in Chicago, New York City, and San Diego. These architectural firms were given three criteria: single cells for inmates, direct supervision by staff, and functional living units. The concept of direct supervision, by which staff and inmates share a common area, had practical significance. No longer were inmates locked in cells with other inmates out of sight from jail personnel. In these new-generation jails, inmates and staff share the facility, with jail personnel in constant contact with the inmates. Jail personnel actually occupy a space within the dayroom or housing pod. Each living unit is made up of manageable groups of between 16 and 46 inmates. The ultimate goal of the new-generation jail is to provide a safe, violence-free environment for both inmates and staff that treats inmates in a humane fashion