Is it Legal to use? In Canada, Radar Detectors are legal to use in province of AB, BC, SK and are illegal in NB, MB, ON, QC, NS, NL, PE, NT, YT, NU. In USA, Radar detectors are completely legal to use in noncommercial vehicles in 49 states. Virginia and Washington DC are the only places in the United States that currently ban radar detectors. Radar detector use in commercial vehicles has been prohibited in the U.S. since 1995.