Ice　on　the　road　surface　can　cause　vehicles　to　skid,　overturn,　and　tailgate,　which　can　seriously　compromise　the　safety　of　traffic　operations.　To　avoid　traffic　accidents,　it　is　necessary　to　identify　the　icy　state　of　the　road.　A　piezoelectric　sensor　was　designed　for　automating　the　detection　of　icing.　The　sensors　were　calibrated　in　various　icing　scenarios,　and　their　accuracy　was　tested　in　a　variety　of　operational　situations.　Eventually,　the　sensors　were　trialed　on　a　national　road　in　Qinghai　Province.　The　results　show　that,　under　different　working　conditions,　the　sensor　is　capable　of　detecting　the　thickness　of　ice　on　the　road　surface　with　a　resolution　of　0.1mm　and　an　accuracy　of　no　less　than　95%.　The　piezoelectric　sensors　can　serve　in　the　natural　environment　of　the　road　for　a　long　time　and　provide　a　technical　reference　for　automatic　road　detection.