for use ADS was developed as a non-lethal weapon. According to Department of Defense policy, non-lethal weapons "are explicitly designed and primarily employed so as to incapacitate personnel or material, while minimizing fatalities, permanent injury to personnel, and undesired damage to property and the environment." ADS has applications for crowd control and perimeter defense, and filling "the gap between shouting and shooting." Other crowd control methods – including pepper spray, tear gas, water cannons, slippery foam and rubber bullets – carry implicit dangers of temporary or permanent injury or accidental death, and often leave residue or residual material. Combinations of acoustic and optical system platforms with ADS can be used to effectively communicate to, warn of escalation of force, introduce optical and auditory deterrents and step function the escalation of transmitted force from relatively benign to ultimately forced dispersal of a crowd, or to deny them from an area or access to an area. A group of people can theoretically be dispersed or induced to leave an area in a manner unlikely to damage personnel, non-involved civilians (no stray bullets), or to nearby buildings or the environment. Non-lethal weapons are intended to provide options to U.S. troops, for example, "to stop suspicious vehicles without killing the drivers". Although the ADS millimeter wave frequency does not affect a car's electronic components, it can be used to deter a driver in an approaching vehicle. In a broader strategic context, non-lethal weapons such as ADS have the potential to offer "precision, accuracy, and effective duration that can help save military and civilian lives, break the cycle of violence by offering a more graduated response, and even prevent violence from occurring if the opportunity for early or preclusionary engagement arises." The Council on Foreign Relations noted that "wider integration of existing types of nonlethal weapons (NLW) into the U.S. Army and Marine Corps could have helped to reduce the damage done by widespread looting and sabotage after the cessation of major conflict in Iraq." In Afghanistan, the need to minimize civilian casualties has led to restrictive rules of engagement on the use of lethal force by US troops. A National Public Radio correspondent in Afghanistan "witnessed troops grappling with the dilemma of whether to shoot." Non-lethal weapons such as ADS provide an option for US forces in those situations. Controversy The effects of this radio frequency on humans have been studied by the military