Massachusetts Supreme Court First to Recognize ALPRs Can Constitute a Fourth Amendment Search

In Commonwealth v. McCarthy, the Massachusetts Supreme Judicial Court became the first appellate court to recognize that ALPRs can constitute a Fourth Amendment search at sufficient scale, applying the 'mosaic theory' that aggregated location data from plate readers can reveal intimate details of a person's life. On the facts before it — four cameras on two bridges — the court held that McCarthy's own privacy interest had not been invaded, leaving the constitutional question open for larger networks.