The Atlantic Cities recently ran an article highlighting all the great things about the new streetlights being used in Chattanooga, TN. The LED streetlights are more efficient and save the city money, but can also be controlled wirelessly to dim or flash depending on the needs of the city and the police. Beyond this, the streetlights also have the ability to do something much more controversial: analyze air samples to detect meth labs. Certainly combating meth addiction and reducing the number of meth labs is great for society and individual neighborhoods. Even advocates for looser or no drug regulation recognize the inherent danger of meth that is not necessarily present with many other commonly used illegal drugs. But let’s not let a detection device that targets a widely disliked drug cloud the infringement of privacy presented by the use of such devices.

Recent rulings by the Supreme Court on the use of similar detection tactics present a less-than-clear picture regarding constitutionality. In 2001, the Court ruled against the use of thermal imaging equipment by police to detect marijuana grow houses. Growing marijuana requires extensive use of heat lamps, so simply monitoring the heat emanating from a house may be a good indication of what is going on inside the house. The majority opinion, written by Justice Scalia, said any sense-enhancing technology used to measure the interior of a house that could not otherwise be measured without physical intrusion constitutes a search. It was important to the Court that the technology used was not widely available to the public. Scalia also said the use of such a device constituted a warrantless search even though the device was only gathering heat radiating from the walls of a house and not heat actually inside the house. Lastly, the Court disapproved of the ability for thermal-imaging to reveal “intimate details” of the household without revealing any illegal activity. See Kyllo v. United States, 121 S. Ct. 2038 (2001).

However, in 2005, the Court ruled that it was constitutional for police to use a narcotics-detecting dog to sniff around the outside of a car. In the case, a car was pulled over for a routine traffic violation and police had no reasonable suspicion the car contained any illegal drugs. A second police officer arrived and walked around the car with a narcotics-detecting dog. The dog indicated the presence of drugs and the police searched the car and found marijuana. The Court said this did not infringe on 4th Amendment rights as long as police did not detain the car longer than the time needed to issue a common traffic violation ticket and a well-trained narcotics-detection dog was used. A well-trained dog does not run the risk of exposing intimate details, so the concern in Kyllo was not present in this case. See Illinois v. Caballes, 125 S. Ct. 834 (2005). This past February, in Florida v. Harris, the Court unanimously ruled that an indication by a well-trained narcotics-detecting dog does provide probable cause for a search.

The Caballes case is a terrible decision that is difficult to square with Kyllo. If the Court in Kyllo was concerned that thermal-imaging equipment would reveal intimate details without revealing any illegal activity then the same should  certainly be said for the use of narcotics-detecting dogs. Even a well-trained dog could be incorrect upwards of 90% of the time (Jacob Sullum has a great article about this). The Court in Kyllo was concerned that police were using sense-enhancing equipment not available to the general public. A well-trained narcotics-detecting dog likely fits into both of those categories. So probable cause can be obtained by police through analyzing the air outside of a car using a dog (a dog that could be incorrect 9 times out of 10), but cannot be obtained by analyzing the air outside of a house using thermal-imaging equipment. Perhaps the Justices, mainly the more conservative Justices, value privacy involving real property more than privacy involving other circumstances.  Hopefully we will have a better understanding of this once the Court issues a decision in Florida v. Jardines, a case it heard along with Florida v. Harris involving a narcotics-detecting dog used during a warrantless search on the steps of a home.

Is a streetlamp that analyzes the air for meth more similar to a narcotics-detecting dog or thermal-imaging equipment? For me the answer is the latter. If police are not allowed to analyze the heat emanating from a house, why should they be able to analyze the air particles emanating from a house? This is a sense-enhancing tool not available to the general public, which could expose intimate details without exposing any illegal activity. The circumstances seem similar to those in Kyllo, but then again the circumstances in Caballes seemed similar to those in Kyllo and the Court disagreed. If the Court does value privacy involving the home more than other circumstances then they may be more willing to find meth-detecting streetlamps to be unconstitutional. But the streetlamp is dissimilar to thermal-imaging equipment used in Kyllo in that it does not focus on a single house, so maybe it is okay. But what then would police be able to do with the data? If a streetlamp detects meth, does that give police probable cause to search every house in a 1-mile radius? I don’t think yes would be the answer (I sure hope not). If a streetlamp sits directly outside of a house then any detection could be attributed to that house and it again becomes very similar to Kyllo. It is not really clear how this streetlamp will be used, but my sense is that the Court generally disagrees with any surveillance focused on a specific home.

Obviously eradicating meth use is a high priority, but we should put limits on just how much surveillance can be done. If we allow police to constantly detect meth because we all agree this is a bad drug, what is next? We don’t know what type of technology will exist in the near future that will allow the quick detection of more intimate details. Allowing the government to analyze the air for meth could lead to analyzing the air for people with HIV or people with alcoholism (maybe this is a far stretch right now, but it could happen!).  This technology gives governments an easier path to criminalize drug users when society is increasingly demanding the decriminalization of many drugs.  We need to enhance our expectations of privacy outside of the home to combat government intervention into our intimate lives. The possible disclosure of intimate details or the disclosure of something general like trace amounts of an illegal substance on our clothes only acts to discourage physical human interaction. Surveillance of this nature encourages us to never leave our homes. This is not a great way to build strong communities that foster the exchange of information and promote human interaction.