A recent series of new technology rulings by courts in Ohio have indicated that, so far, Ohio law does not require that police departments obtain search warrants in order to place a GPS tracking device on a suspect's car. With today's technology, a small GPS device can be attached to a suspect's car, and the police can sit at a computer and simply track where that car goes (and record that tracking). Various defendants who have been arrested and prosecuted for crimes which included this type of evidence have moved the courts to suppress that GPS evidence - claiming that the police needed a search warrant before the GPS device is used. Newspapers are following this issue
Normally, police have to obtain a search warrant in order to set up video or audio surveillance of buildings and rooms used by suspects, and they also have to obtain search warrants to monitor phone calls. However, police do not have to obtain search warrants to simply follow a suspect around town - be it on foot or in a car. One Ohio appellate court to address this GPS tracking issue so far has concluded that using GPS tracking technology is more akin to following a suspect on the street rather than eavesdropping on that suspect's conversations with wiretaps or video/audio monitoring. The Court also stated that there is no real "expectation of privacy" on the outside of a car (which is where the GPS device was placed) - even in the undercarriage area of the car.
This issue will obviously have to be decided by the Ohio Supreme Court. However, the highest courts in other states have determined that a warrant is necessary to use GPS technology. Stay tuned.