Analysis of Fog Occurrence and Its Impacts on Road Traffic in the Harmattan Season in Plateau State

Fog formation during the harmattan season poses significant road safety hazards across the elevated terrain of Plateau State, where cool nighttime temperatures and dry continental air masses create conditions conducive to radiation fog. This study analyzes the seasonal frequency, diurnal timing, and spatial distribution of fog events in Plateau State and examines their documented impact on road traffic safety using visibility records from the Jos meteorological station for 2018 to 2023. Accident records obtained from the Federal Road Safety Corps (FRSC) Plateau State command were cross-referenced with visibility data to identify meteorologically attributable incidents. Statistical analysis reveals that fog occurrence is most frequent in December and January, with peak events between 05:00 and 08:00 local time, coinciding with peak rural-to-urban commuter traffic hours. Fog events reducing visibility below 200 metres account for 18 percent of all recorded vehicular accidents on the Jos-Abuja expressway during the study period, with fatal outcomes disproportionately common in the 05:00 to 07:00 window. The study also identifies unlit sections of major highways as compounding risk factors during foggy conditions. Recommendations include installation of fog detection and warning systems at high-risk road sections, public awareness campaigns ahead of harmattan, and mandatory use of fog lights in relevant traffic regulations. Keywords: fog, harmattan, road safety, Plateau State, visibility.