In　order　to　further　improve　the　traffic　safety　service　and　emergency　control　of　highway　under　adverse　weather,　and　to　solve　the　problems　of　high　traffic　accidents　rate　and　low　traffic　efficiency　of　highway　under　the　weather　of　traffic　hazard　-　fog,　this　paper　proposed　a　traffic　risk-oriented　classification　and　control　strategy　for　emergency　situations.　By　analyzing　the　psychological　and　behavioral　characteristics　of　drivers　in　foggy　weather,　it　is　proposed　that　the　decreases　in　driver＇s　visual　recognition　distance　is　the　main　causation　of　traffic　disasters　risk　in　foggy　weather.　Based　on　the　impact　degree　of　drivers＇　visual　recognition　distance　decrease　on　operating　speed,　the　weather　of　traffic　hazard　-　fog　in　highway　is　divided　into　three　risk　levels:　high,　medium　and　low.　Then　by　using　the　relationship　model　between　visibility　in　foggy　weather　and　driver＇s　visual　recognition　distance,　the　study　proposes　the　corresponding　index　thresholds　of　the　early　warning　management　and　speed　limit　management　for　different　risk　levels　of　highway,　and　specifies　the　setting　principles　and　length　of　the　early　warning　section,　finally　forms　a　set　of　refined　traffic　emergency　classification　and　control　scheme　for　highway　foggy　segment.　©The　Institution　of　Engineering　&　Technology　2023.