When police officers in New Jersey and around the country initiate traffic stops and suspect drugs may be concealed in the vehicles they pull over, they often call K-9 units to the scene. Police dogs are trained to alert when they detect traces of illegal narcotics, and the courts have generally held that such an alert gives police officers the probable cause they need to conduct a more rigorous search. However, the results of a recent study of 139 traffic stops suggest that drugs are only found in about half of these searches.
Investigators from a Kentucky newspaper found that when drugs are discovered during a search initiated by a K-9 unit, officers often found only trace or residual amounts of marijuana. Some of these searches were logged as successful while others were considered by K-9 handlers to be unsuccessful. The public tend to view police dogs as being extremely efficient, but that is largely the result of media outlets reporting at length about significant drug seizures while ignoring unsuccessful searches.
Supreme Court Justice Justice David Souter pointed this out when he rendered his opinion in a 2005 case involving the use of police dogs during traffic stops. The court ruled that such use did not violate the Fourth Amendment protection against unreasonable search and seizure, but Justice Souter said in his opinion that the capabilities of police dogs were greatly exaggerated. Eight years later, the Supreme Court ruled that K-9 units must be certified at least once a year.
When their clients have been charged with drug possession following a vehicle search initiated by a police dog, experienced criminal defense attorneys may study the timeline in police reports carefully. This is because the Supreme Court has ruled that police officers cannot lengthen traffic stops unreasonably to give police dogs time to reach the scene.
Source: The U.S. Supreme Court, “Rodriguez v. United States”, accessed on May 12, 2020