Under the current law, investigators and police departments routinely install secret GPS devices on cars and cellphones without being required to first obtain a warrant. Judges in Florida, and elsewhere, have said tracking on public roads using GPS signals is no different than an officer following a suspect on a public highway, but critics are concerned that the installation of such devices constitutes an unlawful search and intrusion of privacy under the 4th Amendment. The US Supreme Court is set to render a decision this fall which could potentially force police departments to seek a warrant prior to installing GPS tracking devices.